[syzbot] [net?] [bpf?] general protection fault in __dev_flush

[syzbot] [net?] [bpf?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    68b59730459e Merge tag 'perf-tools-for-v6.11-2024-07-16' o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14cb0ab5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b6230d83d52af231
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8229997a3dbb/disk-68b59730.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd51823e0836/vmlinux-68b59730.xz
kernel image: https://storage.googleapis.com/syzbot-assets/01811b27f987/bzImage-68b59730.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xfbd5a5d5a0000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0xdead4ead00000008-0xdead4ead0000000f]
CPU: 1 PID: 8860 Comm: syz.0.1070 Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:__list_del include/linux/list.h:195 [inline]
RIP: 0010:__list_del_clearprev include/linux/list.h:209 [inline]
RIP: 0010:__dev_flush+0xe4/0x160 kernel/bpf/devmap.c:428
Code: b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 49 89 c5 74 08 48 89 df e8 6a c3 3d 00 48 8b 2b 48 8d 5d 08 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 3d c4 3d 00 4c 89 23 4c 89 e0 48
RSP: 0018:ffffc90000a18af0 EFLAGS: 00010212
RAX: 1bd5a9d5a0000001 RBX: dead4ead00000008 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff8880b943e868
RBP: dead4ead00000000 R08: ffff8880b943e867 R09: ffff8880b943e858
R10: dffffc0000000000 R11: ffffed1017287d0d R12: 00000000ffffffff
R13: dffffc0000000000 R14: ffff8880b943e848 R15: 1ffff11017287d09
FS:  00007f33633c96c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000054f40000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 xdp_do_check_flushed+0x129/0x240 net/core/filter.c:4300
 __napi_poll+0xe4/0x490 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6962
 handle_softirqs+0x2c6/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 common_interrupt+0xaa/0xd0 arch/x86/kernel/irq.c:278
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5062
Code: c9 50 e8 19 b6 0b 00 48 83 c4 08 4c 89 f7 e8 7d 38 00 00 e9 de 04 00 00 4c 89 f7 e8 d0 d9 32 0a e8 4b e8 36 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90003a377a8 EFLAGS: 00000286
RAX: 94ed15acce52c200 RBX: ffff88807e01da00 RCX: ffffffff947db703
RDX: dffffc0000000000 RSI: ffffffff8bcac9a0 RDI: ffffffff8c205b20
RBP: ffffc90003a377f0 R08: ffffffff8faec7af R09: 1ffffffff1f5d8f5
R10: dffffc0000000000 R11: fffffbfff1f5d8f6 R12: 1ffff110172a7ebb
R13: dffffc0000000000 R14: ffff8880b943e840 R15: ffff8880b953f5d8
 context_switch kernel/sched/core.c:5191 [inline]
 __schedule+0x1808/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 futex_wait_queue+0x14e/0x1d0 kernel/futex/waitwake.c:370
 __futex_wait+0x17f/0x320 kernel/futex/waitwake.c:669
 futex_wait+0x101/0x360 kernel/futex/waitwake.c:697
 do_futex+0x33b/0x560 kernel/futex/syscalls.c:102
 __do_sys_futex kernel/futex/syscalls.c:179 [inline]
 __se_sys_futex+0x3f9/0x480 kernel/futex/syscalls.c:160
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3362575b59
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f33633c90f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f3362705f68 RCX: 00007f3362575b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3362705f68
RBP: 00007f3362705f60 R08: 00007f33633c96c0 R09: 00007f33633c96c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3362705f6c
R13: 000000000000000b R14: 00007ffec9a21080 R15: 00007ffec9a21168
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del include/linux/list.h:195 [inline]
RIP: 0010:__list_del_clearprev include/linux/list.h:209 [inline]
RIP: 0010:__dev_flush+0xe4/0x160 kernel/bpf/devmap.c:428
Code: b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 49 89 c5 74 08 48 89 df e8 6a c3 3d 00 48 8b 2b 48 8d 5d 08 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 3d c4 3d 00 4c 89 23 4c 89 e0 48
RSP: 0018:ffffc90000a18af0 EFLAGS: 00010212
RAX: 1bd5a9d5a0000001 RBX: dead4ead00000008 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff8880b943e868
RBP: dead4ead00000000 R08: ffff8880b943e867 R09: ffff8880b943e858
R10: dffffc0000000000 R11: ffffed1017287d0d R12: 00000000ffffffff
R13: dffffc0000000000 R14: ffff8880b943e848 R15: 1ffff11017287d09
FS:  00007f33633c96c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000054f40000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	b8 00 00 00 00       	mov    $0x0,%eax
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	(bad)
   8:	df 41 80             	filds  -0x80(%rcx)
   b:	7c 05                	jl     0x12
   d:	00 00                	add    %al,(%rax)
   f:	49 89 c5             	mov    %rax,%r13
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 6a c3 3d 00       	call   0x3dc386
  1c:	48 8b 2b             	mov    (%rbx),%rbp
  1f:	48 8d 5d 08          	lea    0x8(%rbp),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 3d c4 3d 00       	call   0x3dc476
  39:	4c 89 23             	mov    %r12,(%rbx)
  3c:	4c 89 e0             	mov    %r12,%rax
  3f:	48                   	rex.W


---
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Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    7846b618e0a4 Merge tag 'rtc-6.11' of git://git.kernel.org/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=142d3eb5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=be4129de17851dbe
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=154c40b1980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14f3e11d980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-7846b618.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3a2831ffe61c/vmlinux-7846b618.xz
kernel image: https://storage.googleapis.com/syzbot-assets/575e23a7c452/bzImage-7846b618.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 5389 Comm: syz-executor357 Not tainted 6.10.0-syzkaller-11323-g7846b618e0a4 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__dev_flush+0x49/0x1e0 kernel/bpf/devmap.c:424
Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 98 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2f 48 8d 5d 80 48 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 69 01 00 00 48 8b 45 00 49 39 ef 4c 8d 60 80 0f
RSP: 0018:ffffc900008b0c90 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffffffffff80 RCX: ffffffff88d6a5bb
RDX: 0000000000000000 RSI: ffffffff81af9c56 RDI: ffffc9000345fa68
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc9000345fa58
R13: ffff888022ec0fb0 R14: ffffc9000345fa68 R15: ffffc9000345fa68
FS:  0000555568ea6380(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff4743880f0 CR3: 0000000023168000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 xdp_do_check_flushed+0x40a/0x4e0 net/core/filter.c:4300
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 do_softirq kernel/softirq.c:455 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:442
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_get_user+0x1d9b/0x3c30 drivers/net/tun.c:1936
 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2052
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x6b6/0x1140 fs/read_write.c:590
 ksys_write+0x12f/0x260 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff47430af50
Code: 40 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d 51 e1 07 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89
RSP: 002b:00007ffde0326728 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffde03267c0 RCX: 00007ff47430af50
RDX: 0000000000000e80 RSI: 0000000020000100 RDI: 00000000000000c8
RBP: 00007ffde0326770 R08: 00007ffde0326750 R09: 00007ffde0326750
R10: 00007ffde0326750 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__dev_flush+0x49/0x1e0 kernel/bpf/devmap.c:424
Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 98 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2f 48 8d 5d 80 48 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 69 01 00 00 48 8b 45 00 49 39 ef 4c 8d 60 80 0f
RSP: 0018:ffffc900008b0c90 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffffffffff80 RCX: ffffffff88d6a5bb
RDX: 0000000000000000 RSI: ffffffff81af9c56 RDI: ffffc9000345fa68
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc9000345fa58
R13: ffff888022ec0fb0 R14: ffffc9000345fa68 R15: ffffc9000345fa68
FS:  0000555568ea6380(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff4743880f0 CR3: 0000000023168000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 85 98 01 00 00    	jne    0x1a6
   e:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  15:	fc ff df
  18:	49 8b 2f             	mov    (%r15),%rbp
  1b:	48 8d 5d 80          	lea    -0x80(%rbp),%rbx
  1f:	48 89 ea             	mov    %rbp,%rdx
  22:	48 c1 ea 03          	shr    $0x3,%rdx
* 26:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2a:	0f 85 69 01 00 00    	jne    0x199
  30:	48 8b 45 00          	mov    0x0(%rbp),%rax
  34:	49 39 ef             	cmp    %rbp,%r15
  37:	4c 8d 60 80          	lea    -0x80(%rax),%r12
  3b:	0f                   	.byte 0xf


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

[Jeongjun Park]

In the previous commit, bpf_net_context handling was added to 
tun_sendmsg() and do_xdp_generic(), but if you write code like this,
bpf_net_context overlaps in the call trace below, causing various
memory corruptions.

<Call trace>
...
tun_sendmsg() // bpf_net_ctx_set()
  tun_xdp_one()
    do_xdp_generic() // bpf_net_ctx_set() <-- nested
...

This patch removes the bpf_net_context handling that exists in 
do_xdp_generic() and modifies it to handle it in the parent function.

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
---
 drivers/net/tun.c | 3 +++
 net/core/dev.c    | 8 +++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9b24861464bc..095ada4a525e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1919,10 +1919,12 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 	if (skb_xdp) {
 		struct bpf_prog *xdp_prog;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 		int ret;
 
 		local_bh_disable();
 		rcu_read_lock();
+		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		xdp_prog = rcu_dereference(tun->xdp_prog);
 		if (xdp_prog) {
 			ret = do_xdp_generic(xdp_prog, &skb);
@@ -1932,6 +1934,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 				goto unlock_frags;
 			}
 		}
+		bpf_net_ctx_clear(bpf_net_ctx);
 		rcu_read_unlock();
 		local_bh_enable();
 	}
diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..26f9fdd66e64 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5126,14 +5126,11 @@ static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);
 
 int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 {
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
-
 	if (xdp_prog) {
 		struct xdp_buff xdp;
 		u32 act;
 		int err;
 
-		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);
 		if (act != XDP_PASS) {
 			switch (act) {
@@ -5147,13 +5144,11 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 				generic_xdp_tx(*pskb, xdp_prog);
 				break;
 			}
-			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
 	}
 	return XDP_PASS;
 out_redir:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);
 	return XDP_DROP;
 }
@@ -5475,10 +5470,13 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 
 	if (static_branch_unlikely(&generic_xdp_needed_key)) {
 		int ret2;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 
 		migrate_disable();
+		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
 				      &skb);
+		bpf_net_ctx_clear(bpf_net_ctx);
 		migrate_enable();
 
 		if (ret2 != XDP_PASS) {
--

Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

[Willem de Bruijn]

Jeongjun Park wrote:
> In the previous commit, bpf_net_context handling was added to 
> tun_sendmsg() and do_xdp_generic(), but if you write code like this,
> bpf_net_context overlaps in the call trace below, causing various
> memory corruptions.

I'm no expert on this code, but commit 401cb7dae813 that introduced
bpf_net_ctx_set explicitly states that nested calls are allowed.

And the function does imply that:

static inline struct bpf_net_context *bpf_net_ctx_set(struct bpf_net_context *bpf_net_ctx)
{
        struct task_struct *tsk = current;

        if (tsk->bpf_net_context != NULL)
                return NULL;
        bpf_net_ctx->ri.kern_flags = 0;

        tsk->bpf_net_context = bpf_net_ctx;
        return bpf_net_ctx;
}


 
> <Call trace>
> ...
> tun_sendmsg() // bpf_net_ctx_set()
>   tun_xdp_one()
>     do_xdp_generic() // bpf_net_ctx_set() <-- nested
> ...
> 
> This patch removes the bpf_net_context handling that exists in 
> do_xdp_generic() and modifies it to handle it in the parent function.

Is tun_xdp_one missing? That also calls do_xdp_generic.

Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

[Jeongjun Park]

Willem de Bruijn wrote:
> I'm no expert on this code, but commit 401cb7dae813 that introduced
> bpf_net_ctx_set explicitly states that nested calls are allowed.
>
> And the function does imply that:
>
> static inline struct bpf_net_context *bpf_net_ctx_set(struct bpf_net_context *bpf_net_ctx)
> {
>         struct task_struct *tsk = current;
>
>         if (tsk->bpf_net_context != NULL)
>                 return NULL;
>         bpf_net_ctx->ri.kern_flags = 0;
>
>         tsk->bpf_net_context = bpf_net_ctx;
>         return bpf_net_ctx;
> }

I'm not an expert on this code either. As you said, there is a 
possibility that the bug is not caused by overlapping calls, but various
memory corruptions are occurring due to the handling of bpf_net_context 
in do_xdp_generic. Therefore, it is appropriate to modify it to handle
it in the parent function rather than in do_xdp_generic.

> Is tun_xdp_one missing? That also calls do_xdp_generic.

This is no problem since tun_xdp_one is only called from tun_sendmsg 
and tun_sendmsg already does the bpf_net_context handling.

Regards,
Jeongjun Park.

Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

[Paolo Abeni]

On 7/25/24 04:43, Willem de Bruijn wrote:
> Jeongjun Park wrote:
>> In the previous commit, bpf_net_context handling was added to
>> tun_sendmsg() and do_xdp_generic(), but if you write code like this,
>> bpf_net_context overlaps in the call trace below, causing various
>> memory corruptions.
> 
> I'm no expert on this code, but commit 401cb7dae813 that introduced
> bpf_net_ctx_set explicitly states that nested calls are allowed.
> 
> And the function does imply that:
> 
> static inline struct bpf_net_context *bpf_net_ctx_set(struct bpf_net_context *bpf_net_ctx)
> {
>          struct task_struct *tsk = current;
> 
>          if (tsk->bpf_net_context != NULL)
>                  return NULL;
>          bpf_net_ctx->ri.kern_flags = 0;
> 
>          tsk->bpf_net_context = bpf_net_ctx;
>          return bpf_net_ctx;
> }

I agree with Willem, the ctx nesting looks legit generally speaking. 
@Jeongjun: you need to track down more accurately the issue root cause 
and include such info into the commit message.

Skimming over the code I *think* do_xdp_generic() is not cleaning the 
nested context in all the paths before return and that could cause the 
reported issue.

Thanks,

Paolo

Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

[Jeongjun Park]

Paolo Abeni wrote:
>
> On 7/25/24 04:43, Willem de Bruijn wrote:
> > Jeongjun Park wrote:
> >> In the previous commit, bpf_net_context handling was added to
> >> tun_sendmsg() and do_xdp_generic(), but if you write code like this,
> >> bpf_net_context overlaps in the call trace below, causing various
> >> memory corruptions.
> >
> > I'm no expert on this code, but commit 401cb7dae813 that introduced
> > bpf_net_ctx_set explicitly states that nested calls are allowed.
> >
> > And the function does imply that:
> >
> > static inline struct bpf_net_context *bpf_net_ctx_set(struct bpf_net_context *bpf_net_ctx)
> > {
> >          struct task_struct *tsk = current;
> >
> >          if (tsk->bpf_net_context != NULL)
> >                  return NULL;
> >          bpf_net_ctx->ri.kern_flags = 0;
> >
> >          tsk->bpf_net_context = bpf_net_ctx;
> >          return bpf_net_ctx;
> > }
>
> I agree with Willem, the ctx nesting looks legit generally speaking.
> @Jeongjun: you need to track down more accurately the issue root cause
> and include such info into the commit message.
>
> Skimming over the code I *think* do_xdp_generic() is not cleaning the
> nested context in all the paths before return and that could cause the
> reported issue.

Thanks to your comment, I re-read the code and found the root cause.
I will send a patch for that bug.

Regards,
Jeongjun Park

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 include/linux/filter.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index b6672ff61407..22691015d175 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -842,15 +842,15 @@ static inline void bpf_net_ctx_get_all_used_flush_lists(struct list_head **lh_ma
 	if (!IS_ENABLED(CONFIG_BPF_SYSCALL))
 		return;
 
-	lh = &bpf_net_ctx->dev_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->dev_map_flush_list);
 	if (kern_flags & BPF_RI_F_DEV_MAP_INIT && !list_empty(lh))
 		*lh_dev = lh;
 
-	lh = &bpf_net_ctx->cpu_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->cpu_map_flush_list);
 	if (kern_flags & BPF_RI_F_CPU_MAP_INIT && !list_empty(lh))
 		*lh_map = lh;
 
-	lh = &bpf_net_ctx->xskmap_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->xskmap_map_flush_list);
 	if (IS_ENABLED(CONFIG_XDP_SOCKETS) &&
 	    kern_flags & BPF_RI_F_XSK_MAP_INIT && !list_empty(lh))
 		*lh_xsk = lh;
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 7846b618e0a4c3e08888099d1d4512722b39ca99

---
 include/linux/filter.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index b6672ff61407..22691015d175 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -842,15 +842,15 @@ static inline void bpf_net_ctx_get_all_used_flush_lists(struct list_head **lh_ma
 	if (!IS_ENABLED(CONFIG_BPF_SYSCALL))
 		return;
 
-	lh = &bpf_net_ctx->dev_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->dev_map_flush_list);
 	if (kern_flags & BPF_RI_F_DEV_MAP_INIT && !list_empty(lh))
 		*lh_dev = lh;
 
-	lh = &bpf_net_ctx->cpu_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->cpu_map_flush_list);
 	if (kern_flags & BPF_RI_F_CPU_MAP_INIT && !list_empty(lh))
 		*lh_map = lh;
 
-	lh = &bpf_net_ctx->xskmap_map_flush_list;
+	lh = this_cpu_ptr(&bpf_net_ctx->xskmap_map_flush_list);
 	if (IS_ENABLED(CONFIG_XDP_SOCKETS) &&
 	    kern_flags & BPF_RI_F_XSK_MAP_INIT && !list_empty(lh))
 		*lh_xsk = lh;
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/tun.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9b24861464bc..022ffadae2af 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1661,7 +1661,6 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 				     int len, int *skb_xdp)
 {
 	struct page_frag *alloc_frag = &current->task_frag;
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 	struct bpf_prog *xdp_prog;
 	int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 	char *buf;
@@ -1701,7 +1700,6 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 
 	local_bh_disable();
 	rcu_read_lock();
-	bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 	xdp_prog = rcu_dereference(tun->xdp_prog);
 	if (xdp_prog) {
 		struct xdp_buff xdp;
@@ -1730,14 +1728,12 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 		pad = xdp.data - xdp.data_hard_start;
 		len = xdp.data_end - xdp.data;
 	}
-	bpf_net_ctx_clear(bpf_net_ctx);
 	rcu_read_unlock();
 	local_bh_enable();
 
 	return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
 
 out:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	rcu_read_unlock();
 	local_bh_enable();
 	return NULL;
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

[syzbot]

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***

Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/tun.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9b24861464bc..9254bca2813d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1661,7 +1661,6 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 				     int len, int *skb_xdp)
 {
 	struct page_frag *alloc_frag = &current->task_frag;
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 	struct bpf_prog *xdp_prog;
 	int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 	char *buf;
@@ -1701,7 +1700,6 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 
 	local_bh_disable();
 	rcu_read_lock();
-	bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 	xdp_prog = rcu_dereference(tun->xdp_prog);
 	if (xdp_prog) {
 		struct xdp_buff xdp;
@@ -1730,14 +1728,12 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 		pad = xdp.data - xdp.data_hard_start;
 		len = xdp.data_end - xdp.data;
 	}
-	bpf_net_ctx_clear(bpf_net_ctx);
 	rcu_read_unlock();
 	local_bh_enable();
 
 	return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
 
 out:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	rcu_read_unlock();
 	local_bh_enable();
 	return NULL;
@@ -2570,7 +2566,6 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 
 	if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
 	    ctl && ctl->type == TUN_MSG_PTR) {
-		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 		struct tun_page tpage;
 		int n = ctl->num;
 		int flush = 0, queued = 0;
@@ -2579,7 +2574,6 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 
 		local_bh_disable();
 		rcu_read_lock();
-		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 
 		for (i = 0; i < n; i++) {
 			xdp = &((struct xdp_buff *)ctl->ptr)[i];
@@ -2594,7 +2588,6 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 		if (tfile->napi_enabled && queued > 0)
 			napi_schedule(&tfile->napi);
 
-		bpf_net_ctx_clear(bpf_net_ctx);
 		rcu_read_unlock();
 		local_bh_enable();
 
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 net/core/dev.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..ca1d470bc48a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5126,14 +5126,11 @@ static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);
 
 int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 {
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
-
 	if (xdp_prog) {
 		struct xdp_buff xdp;
 		u32 act;
 		int err;
 
-		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);
 		if (act != XDP_PASS) {
 			switch (act) {
@@ -5147,13 +5144,11 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 				generic_xdp_tx(*pskb, xdp_prog);
 				break;
 			}
-			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
 	}
 	return XDP_PASS;
 out_redir:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);
 	return XDP_DROP;
 }
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/tun.c | 3 +++
 net/core/dev.c    | 8 +++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9b24861464bc..095ada4a525e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1919,10 +1919,12 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 	if (skb_xdp) {
 		struct bpf_prog *xdp_prog;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 		int ret;
 
 		local_bh_disable();
 		rcu_read_lock();
+		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		xdp_prog = rcu_dereference(tun->xdp_prog);
 		if (xdp_prog) {
 			ret = do_xdp_generic(xdp_prog, &skb);
@@ -1932,6 +1934,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 				goto unlock_frags;
 			}
 		}
+		bpf_net_ctx_clear(bpf_net_ctx);
 		rcu_read_unlock();
 		local_bh_enable();
 	}
diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..26f9fdd66e64 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5126,14 +5126,11 @@ static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);
 
 int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 {
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
-
 	if (xdp_prog) {
 		struct xdp_buff xdp;
 		u32 act;
 		int err;
 
-		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);
 		if (act != XDP_PASS) {
 			switch (act) {
@@ -5147,13 +5144,11 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 				generic_xdp_tx(*pskb, xdp_prog);
 				break;
 			}
-			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
 	}
 	return XDP_PASS;
 out_redir:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);
 	return XDP_DROP;
 }
@@ -5475,10 +5470,13 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 
 	if (static_branch_unlikely(&generic_xdp_needed_key)) {
 		int ret2;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 
 		migrate_disable();
+		bpf_net_context = bpf_net_ctx_set(&__bpf_net_ctx);
 		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
 				      &skb);
+		bpf_net_ctx_clear(bpf_net_ctx);
 		migrate_enable();
 
 		if (ret2 != XDP_PASS) {
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/tun.c | 3 +++
 net/core/dev.c    | 8 +++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9b24861464bc..095ada4a525e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1919,10 +1919,12 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 	if (skb_xdp) {
 		struct bpf_prog *xdp_prog;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 		int ret;
 
 		local_bh_disable();
 		rcu_read_lock();
+		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		xdp_prog = rcu_dereference(tun->xdp_prog);
 		if (xdp_prog) {
 			ret = do_xdp_generic(xdp_prog, &skb);
@@ -1932,6 +1934,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 				goto unlock_frags;
 			}
 		}
+		bpf_net_ctx_clear(bpf_net_ctx);
 		rcu_read_unlock();
 		local_bh_enable();
 	}
diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..26f9fdd66e64 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5126,14 +5126,11 @@ static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);
 
 int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 {
-	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
-
 	if (xdp_prog) {
 		struct xdp_buff xdp;
 		u32 act;
 		int err;
 
-		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);
 		if (act != XDP_PASS) {
 			switch (act) {
@@ -5147,13 +5144,11 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 				generic_xdp_tx(*pskb, xdp_prog);
 				break;
 			}
-			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
 	}
 	return XDP_PASS;
 out_redir:
-	bpf_net_ctx_clear(bpf_net_ctx);
 	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);
 	return XDP_DROP;
 }
@@ -5475,10 +5470,13 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 
 	if (static_branch_unlikely(&generic_xdp_needed_key)) {
 		int ret2;
+		struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
 
 		migrate_disable();
+		bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
 		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
 				      &skb);
+		bpf_net_ctx_clear(bpf_net_ctx);
 		migrate_enable();
 
 		if (ret2 != XDP_PASS) {
--

Re: [syzbot] Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()

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Subject: Re: [PATCH net] tun: Remove nested call to bpf_net_ctx_set() in do_xdp_generic()
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 net/core/dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..a741000c81d8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5150,6 +5150,8 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
+		
+		bpf_net_ctx_clear(bpf_net_ctx);
 	}
 	return XDP_PASS;
 out_redir:
--

Re: [syzbot] Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush

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Subject: Re: [syzbot] [net?] [bpf?] general protection fault in __dev_flush
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 net/core/dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..a741000c81d8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5150,6 +5150,8 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
+		
+		bpf_net_ctx_clear(bpf_net_ctx);
 	}
 	return XDP_PASS;
 out_redir:
--

[PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Jeongjun Park]

There are cases where do_xdp_generic returns bpf_net_context without 
clearing it. This causes various memory corruptions, so the missing 
bpf_net_ctx_clear must be added.

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
---
 net/core/dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6ea1d20676fb..751d9b70e6ad 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5150,6 +5150,7 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 			bpf_net_ctx_clear(bpf_net_ctx);
 			return XDP_DROP;
 		}
+		bpf_net_ctx_clear(bpf_net_ctx);
 	}
 	return XDP_PASS;
 out_redir:
--

Re: [PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Jason Wang]

On Fri, Jul 26, 2024 at 5:41 AM Jeongjun Park <aha310510@gmail.com> wrote:
>
> There are cases where do_xdp_generic returns bpf_net_context without
> clearing it. This causes various memory corruptions, so the missing
> bpf_net_ctx_clear must be added.
>
> Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> Signed-off-by: Jeongjun Park <aha310510@gmail.com>

Acked-by: Jason Wang <jasowang@redhat.com>

(Looks like the do_xdp_generic() needs some tweak for example we can
merge the two paths for XDP_DROP at least).

Thanks

> ---
>  net/core/dev.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6ea1d20676fb..751d9b70e6ad 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -5150,6 +5150,7 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
>                         bpf_net_ctx_clear(bpf_net_ctx);
>                         return XDP_DROP;
>                 }
> +               bpf_net_ctx_clear(bpf_net_ctx);
>         }
>         return XDP_PASS;
>  out_redir:
> --
>

Re: [PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Willem de Bruijn]

On Thu, Jul 25, 2024 at 10:21 PM Jason Wang <jasowang@redhat.com> wrote:
>
> On Fri, Jul 26, 2024 at 5:41 AM Jeongjun Park <aha310510@gmail.com> wrote:
> >
> > There are cases where do_xdp_generic returns bpf_net_context without
> > clearing it. This causes various memory corruptions, so the missing
> > bpf_net_ctx_clear must be added.
> >
> > Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> > Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> > Signed-off-by: Jeongjun Park <aha310510@gmail.com>
>
> Acked-by: Jason Wang <jasowang@redhat.com>

Reviewed-by: Willem de Bruijn <willemb@google.com>

Re: [PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Jakub Kicinski]

On Fri, 26 Jul 2024 06:40:49 +0900 Jeongjun Park wrote:
> There are cases where do_xdp_generic returns bpf_net_context without 
> clearing it. This causes various memory corruptions, so the missing 
> bpf_net_ctx_clear must be added.
> 
> Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> Signed-off-by: Jeongjun Park <aha310510@gmail.com>

Also likely:

Reported-by: syzbot+3c2b6d5d4bec3b904933@syzkaller.appspotmail.com
Reported-by: syzbot+707d98c8649695eaf329@syzkaller.appspotmail.com

Right?

[PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Jeongjun Park]

Jakub Kicinski wrote:
>
> On Fri, 26 Jul 2024 06:40:49 +0900 Jeongjun Park wrote:
> > There are cases where do_xdp_generic returns bpf_net_context without
> > clearing it. This causes various memory corruptions, so the missing
> > bpf_net_ctx_clear must be added.
> >
> > Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> > Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> > Signed-off-by: Jeongjun Park <aha310510@gmail.com>
>
> Also likely:
>
> Reported-by: syzbot+3c2b6d5d4bec3b904933@syzkaller.appspotmail.com
> Reported-by: syzbot+707d98c8649695eaf329@syzkaller.appspotmail.com
>
> Right?

Yes, both appear to be bugs with the same root cause.

Regards,
Jeongjun Park

Re: [PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[Jeongjun Park]

On Fri, 26 Jul 2024 06:40:49 +0900 Jeongjun Park wrote:
> There are cases where do_xdp_generic returns bpf_net_context without
> clearing it. This causes various memory corruptions, so the missing
> bpf_net_ctx_clear must be added.
>
> Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> Signed-off-by: Jeongjun Park <aha310510@gmail.com>

Reported-by: syzbot+c226757eb784a9da3e8b@syzkaller.appspotmail.com
Reported-by: syzbot+61a1cfc2b6632363d319@syzkaller.appspotmail.com
Reported-by: syzbot+709e4c85c904bcd62735@syzkaller.appspotmail.com

After searching, I found reports with the same root cause, so I added
them.

Re: [PATCH net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Fri, 26 Jul 2024 06:40:49 +0900 you wrote:
> There are cases where do_xdp_generic returns bpf_net_context without
> clearing it. This causes various memory corruptions, so the missing
> bpf_net_ctx_clear must be added.
> 
> Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
> Fixes: fecef4cd42c6 ("tun: Assign missing bpf_net_context.")
> Signed-off-by: Jeongjun Park <aha310510@gmail.com>
> 
> [...]

Here is the summary with links:
  - [net] tun: Add missing bpf_net_ctx_clear() in do_xdp_generic()
    https://git.kernel.org/netdev/net/c/9da49aa80d68

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x355/0x3f0 net/core/filter.c:4298
Read of size 4 at addr ffffc90003387a50 by task syz.0.105/5938

CPU: 0 UID: 0 PID: 5938 Comm: syz.0.105 Not tainted 6.10.0-syzkaller-g933069701c1b-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
 xdp_do_check_flushed+0x355/0x3f0 net/core/filter.c:4298
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__schedule+0xe3f/0x5490 kernel/sched/core.c:6399
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 ba 3f 00 00 48 8b bd 10 ff ff ff 4d 89 77 10 4c 89 f6 e8 c9 a5 0f f6 48 89 c7 e8 61 54 6a f6 <48> 8b 8d a0 fe ff ff 48 b8 00 00 00 00 00 fc ff df 48 01 c1 48 c7
RSP: 0018:ffffc90003387980 EFLAGS: 00000206
RAX: 00000000000001a9 RBX: ffff888043a40000 RCX: 1ffffffff1fce089
RDX: 0000000000000000 RSI: ffffffff8b2cc580 RDI: ffffffff8b90c740
RBP: ffffc90003387b10 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8fe7489f R11: 0000000000000001 R12: ffff88806b03f908
R13: 0000000000000000 R14: ffff888043a40000 R15: ffff88806b03ee00
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6708
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 class_preempt_destructor include/linux/preempt.h:480 [inline]
 class_preempt_destructor include/linux/preempt.h:480 [inline]
 try_to_wake_up+0xc08/0x13e0 kernel/sched/core.c:4022
 wake_up_process kernel/sched/core.c:4299 [inline]
 wake_up_q+0x91/0x140 kernel/sched/core.c:1029
 futex_wake+0x43e/0x4e0 kernel/futex/waitwake.c:199
 do_futex+0x1e5/0x350 kernel/futex/syscalls.c:107
 __do_sys_futex kernel/futex/syscalls.c:179 [inline]
 __se_sys_futex kernel/futex/syscalls.c:160 [inline]
 __x64_sys_futex+0x1e1/0x4c0 kernel/futex/syscalls.c:160
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faaa0975b59
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faaa16670f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007faaa0b05f68 RCX: 00007faaa0975b59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007faaa0b05f6c
RBP: 00007faaa0b05f60 R08: 00007faaa1668080 R09: 00007faaa16676c0
R10: 0000000000000e80 R11: 0000000000000246 R12: 00007faaa0b05f6c
R13: 000000000000000b R14: 00007fff8e045980 R15: 00007fff8e045a68
 </TASK>

The buggy address belongs to stack of task syz.0.105/5938
 and is located at offset 40 in frame:
 __schedule+0x0/0x5490

This frame has 3 objects:
 [48, 52) 'cid'
 [64, 80) 'rf'
 [96, 120) 'ac'

The buggy address belongs to the virtual mapping at
 [ffffc90003380000, ffffc90003389000) created by:
 kernel_clone+0xfd/0x980 kernel/fork.c:2781

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801f49d0f0 pfn:0x1f49d
memcg:ffff88802787e902
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88801f49d0f0 0000000000000000 00000001ffffffff ffff88802787e902
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5663, tgid 5663 (syz-executor), ts 127270798487, free_ts 127240380476
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263
 vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
 __vmalloc_area_node mm/vmalloc.c:3660 [inline]
 __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841
 alloc_thread_stack_node kernel/fork.c:313 [inline]
 dup_task_struct kernel/fork.c:1113 [inline]
 copy_process+0x2f3b/0x8de0 kernel/fork.c:2204
 kernel_clone+0xfd/0x980 kernel/fork.c:2781
 __do_sys_clone+0xba/0x100 kernel/fork.c:2924
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5663 tgid 5663 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2608
 __folio_put+0x31c/0x3e0 mm/swap.c:128
 folio_put include/linux/mm.h:1479 [inline]
 free_page_and_swap_cache+0x249/0x2c0 mm/swap_state.c:308
 __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x89/0xe0 mm/mmu_gather.c:282
 rcu_do_batch kernel/rcu/tree.c:2569 [inline]
 rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2843
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffffc90003387900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003387980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90003387a00: 00 00 00 00 00 f1 f1 f1 f1 f1 f1 04 f2 00 00 f2
                                                 ^
 ffffc90003387a80: f2 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00
 ffffc90003387b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	fa                   	cli
   1:	48 c1 ea 03          	shr    $0x3,%rdx
   5:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   9:	0f 85 ba 3f 00 00    	jne    0x3fc9
   f:	48 8b bd 10 ff ff ff 	mov    -0xf0(%rbp),%rdi
  16:	4d 89 77 10          	mov    %r14,0x10(%r15)
  1a:	4c 89 f6             	mov    %r14,%rsi
  1d:	e8 c9 a5 0f f6       	call   0xf60fa5eb
  22:	48 89 c7             	mov    %rax,%rdi
  25:	e8 61 54 6a f6       	call   0xf66a548b
* 2a:	48 8b 8d a0 fe ff ff 	mov    -0x160(%rbp),%rcx <-- trapping instruction
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 01 c1             	add    %rax,%rcx
  3e:	48                   	rex.W
  3f:	c7                   	.byte 0xc7


Tested on:

commit:         93306970 Merge tag '6.11-rc-smb3-server-fixes' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1162fe3d980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c043ce4607a33671
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1214995e980000

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
Read of size 4 at addr ffffc9000167fa50 by task syz.0.111/5959

CPU: 1 UID: 0 PID: 5959 Comm: syz.0.111 Not tainted 6.10.0-syzkaller-g933069701c1b #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
 xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:230
Code: 48 8b 05 e3 5c 79 7e 48 8b 80 10 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 af 5c 79 7e 65 8b 05 b0 5c
RSP: 0018:ffffc9000167f618 EFLAGS: 00000246
RAX: 0000000000000003 RBX: ffffea0000d86e40 RCX: ffffffff81d6e231
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000005
RBP: ffffea0000d86e40 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000000 R15: ffffc9000167fab8
 __folio_rmap_sanity_checks+0x61/0x550 include/linux/rmap.h:201
 __folio_remove_rmap mm/rmap.c:1514 [inline]
 folio_remove_rmap_ptes+0x31/0x3d0 mm/rmap.c:1595
 zap_present_folio_ptes mm/memory.c:1517 [inline]
 zap_present_ptes mm/memory.c:1576 [inline]
 zap_pte_range mm/memory.c:1618 [inline]
 zap_pmd_range mm/memory.c:1736 [inline]
 zap_pud_range mm/memory.c:1765 [inline]
 zap_p4d_range mm/memory.c:1786 [inline]
 unmap_page_range+0x1997/0x3c10 mm/memory.c:1807
 unmap_single_vma+0x194/0x2b0 mm/memory.c:1853
 unmap_vmas+0x22f/0x490 mm/memory.c:1897
 exit_mmap+0x1b8/0xb20 mm/mmap.c:3382
 __mmput+0x12a/0x480 kernel/fork.c:1345
 mmput+0x62/0x70 kernel/fork.c:1367
 exit_mm kernel/exit.c:571 [inline]
 do_exit+0x9bf/0x2bb0 kernel/exit.c:869
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031
 get_signal+0x25fd/0x2770 kernel/signal.c:2917
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f66e7375b59
Code: Unable to access opcode bytes at 0x7f66e7375b2f.
RSP: 002b:00007f66e809c0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f66e7505f68 RCX: 00007f66e7375b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f66e7505f68
RBP: 00007f66e7505f60 R08: 00007f66e809c6c0 R09: 00007f66e809c6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f66e7505f6c
R13: 000000000000000b R14: 00007ffd814e49e0 R15: 00007ffd814e4ac8
 </TASK>

The buggy address belongs to stack of task syz.0.111/5959
 and is located at offset 24 in frame:
 exit_mmap+0x0/0xb20 mm/mmap.c:3202

This frame has 2 objects:
 [32, 96) 'vmi'
 [128, 256) 'tlb'

The buggy address belongs to the virtual mapping at
 [ffffc90001678000, ffffc90001681000) created by:
 kernel_clone+0xfd/0x980 kernel/fork.c:2781

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801ec13150 pfn:0x1ec13
memcg:ffff8880261f3b82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88801ec13150 0000000000000000 00000001ffffffff ffff8880261f3b82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5636, tgid 5636 (syz-executor), ts 121181133330, free_ts 121100052787
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263
 vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
 __vmalloc_area_node mm/vmalloc.c:3660 [inline]
 __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841
 alloc_thread_stack_node kernel/fork.c:313 [inline]
 dup_task_struct kernel/fork.c:1113 [inline]
 copy_process+0x2f3b/0x8de0 kernel/fork.c:2204
 kernel_clone+0xfd/0x980 kernel/fork.c:2781
 __do_sys_clone+0xba/0x100 kernel/fork.c:2924
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 0 tgid 0 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2608
 __folio_put+0x31c/0x3e0 mm/swap.c:128
 folio_put include/linux/mm.h:1479 [inline]
 free_page_and_swap_cache+0x249/0x2c0 mm/swap_state.c:308
 __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x89/0xe0 mm/mmu_gather.c:282
 rcu_do_batch kernel/rcu/tree.c:2569 [inline]
 rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2843
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffffc9000167f900: 00 f2 f2 f2 00 f2 f2 f2 00 00 f2 f2 00 00 00 00
 ffffc9000167f980: 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00
>ffffc9000167fa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00
                                                 ^
 ffffc9000167fa80: 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00
 ffffc9000167fb00: 00 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	48 8b 05 e3 5c 79 7e 	mov    0x7e795ce3(%rip),%rax        # 0x7e795cea
   7:	48 8b 80 10 16 00 00 	mov    0x1610(%rax),%rax
   e:	c3                   	ret
   f:	cc                   	int3
  10:	cc                   	int3
  11:	cc                   	int3
  12:	cc                   	int3
  13:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
  27:	90                   	nop
  28:	90                   	nop
  29:	90                   	nop
* 2a:	49 89 d2             	mov    %rdx,%r10 <-- trapping instruction
  2d:	49 89 f8             	mov    %rdi,%r8
  30:	49 89 f1             	mov    %rsi,%r9
  33:	65 48 8b 15 af 5c 79 	mov    %gs:0x7e795caf(%rip),%rdx        # 0x7e795cea
  3a:	7e
  3b:	65                   	gs
  3c:	8b                   	.byte 0x8b
  3d:	05                   	.byte 0x5
  3e:	b0 5c                	mov    $0x5c,%al


Tested on:

commit:         93306970 Merge tag '6.11-rc-smb3-server-fixes' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17687d79980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c043ce4607a33671
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x355/0x3f0 net/core/filter.c:4298
Read of size 4 at addr ffffc9000336fa50 by task syz.0.70/5863

CPU: 1 PID: 5863 Comm: syz.0.70 Not tainted 6.10.0-syzkaller-11323-g7846b618e0a4-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
 xdp_do_check_flushed+0x355/0x3f0 net/core/filter.c:4298
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__schedule+0xe3f/0x5490 kernel/sched/core.c:6399
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 ba 3f 00 00 48 8b bd 10 ff ff ff 4d 89 77 10 4c 89 f6 e8 b9 6e 0f f6 48 89 c7 e8 71 e8 69 f6 <48> 8b 8d a0 fe ff ff 48 b8 00 00 00 00 00 fc ff df 48 01 c1 48 c7
RSP: 0018:ffffc9000336f980 EFLAGS: 00000206
RAX: 000000000000018b RBX: ffff8880256b0000 RCX: 1ffffffff1fce461
RDX: 0000000000000000 RSI: ffffffff8b2cbac0 RDI: ffffffff8b909e40
RBP: ffffc9000336fb10 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8fe7675f R11: 0000000000000001 R12: ffff88806b13f788
R13: 0000000000000000 R14: ffff8880256b0000 R15: ffff88806b13ec80
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6708
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 class_preempt_destructor include/linux/preempt.h:480 [inline]
 class_preempt_destructor include/linux/preempt.h:480 [inline]
 try_to_wake_up+0xc08/0x13e0 kernel/sched/core.c:4022
 wake_up_process kernel/sched/core.c:4299 [inline]
 wake_up_q+0x91/0x140 kernel/sched/core.c:1029
 futex_wake+0x43e/0x4e0 kernel/futex/waitwake.c:199
 do_futex+0x1e5/0x350 kernel/futex/syscalls.c:107
 __do_sys_futex kernel/futex/syscalls.c:179 [inline]
 __se_sys_futex kernel/futex/syscalls.c:160 [inline]
 __x64_sys_futex+0x1e1/0x4c0 kernel/futex/syscalls.c:160
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc830f75b59
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc831d8e0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fc831105f68 RCX: 00007fc830f75b59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fc831105f6c
RBP: 00007fc831105f60 R08: 00007fc831d8f080 R09: 00007fc831d8e6c0
R10: 0000000000000e80 R11: 0000000000000246 R12: 00007fc831105f6c
R13: 000000000000000b R14: 00007ffea9d2b330 R15: 00007ffea9d2b418
 </TASK>

The buggy address belongs to stack of task syz.0.70/5863
 and is located at offset 40 in frame:
 __schedule+0x0/0x5490

This frame has 3 objects:
 [48, 52) 'cid'
 [64, 80) 'rf'
 [96, 120) 'ac'

The buggy address belongs to the virtual mapping at
 [ffffc90003368000, ffffc90003371000) created by:
 kernel_clone+0xfd/0x980 kernel/fork.c:2780

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802b714360 pfn:0x2b714
memcg:ffff888021296f02
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88802b714360 0000000000000000 00000001ffffffff ffff888021296f02
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5862, tgid 5862 (syz.0.70), ts 130256428069, free_ts 129532353425
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1473
 prep_new_page mm/page_alloc.c:1481 [inline]
 get_page_from_freelist+0x1353/0x2e50 mm/page_alloc.c:3425
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4683
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265
 vm_area_alloc_pages mm/vmalloc.c:3583 [inline]
 __vmalloc_area_node mm/vmalloc.c:3659 [inline]
 __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3840
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct kernel/fork.c:1111 [inline]
 copy_process+0x2f3b/0x8de0 kernel/fork.c:2203
 kernel_clone+0xfd/0x980 kernel/fork.c:2780
 __do_sys_clone3+0x1f5/0x270 kernel/fork.c:3084
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5829 tgid 5828 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1093 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2588
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:468
 exit_mmap+0x3d1/0xb20 mm/mmap.c:3354
 __mmput+0x12a/0x480 kernel/fork.c:1343
 mmput+0x62/0x70 kernel/fork.c:1365
 exit_mm kernel/exit.c:566 [inline]
 do_exit+0x9bf/0x2bb0 kernel/exit.c:864
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1026
 get_signal+0x25fb/0x2770 kernel/signal.c:2917
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc9000336f900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000336f980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000336fa00: 00 00 00 00 00 f1 f1 f1 f1 f1 f1 04 f2 00 00 f2
                                                 ^
 ffffc9000336fa80: f2 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00
 ffffc9000336fb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	fa                   	cli
   1:	48 c1 ea 03          	shr    $0x3,%rdx
   5:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   9:	0f 85 ba 3f 00 00    	jne    0x3fc9
   f:	48 8b bd 10 ff ff ff 	mov    -0xf0(%rbp),%rdi
  16:	4d 89 77 10          	mov    %r14,0x10(%r15)
  1a:	4c 89 f6             	mov    %r14,%rsi
  1d:	e8 b9 6e 0f f6       	call   0xf60f6edb
  22:	48 89 c7             	mov    %rax,%rdi
  25:	e8 71 e8 69 f6       	call   0xf669e89b
* 2a:	48 8b 8d a0 fe ff ff 	mov    -0x160(%rbp),%rcx <-- trapping instruction
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 01 c1             	add    %rax,%rcx
  3e:	48                   	rex.W
  3f:	c7                   	.byte 0xc7


Tested on:

commit:         7846b618 Merge tag 'rtc-6.11' of git://git.kernel.org/..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11d729b5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=be4129de17851dbe
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=148939c3980000

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
Read of size 4 at addr ffffc9000331fa50 by task syz.0.36/5802

CPU: 0 UID: 0 PID: 5802 Comm: syz.0.36 Not tainted 6.10.0-syzkaller-12246-g786c8248dbd3-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
 xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_call_function arch/x86/kernel/smp.c:257 [inline]
 sysvec_call_function+0x95/0xb0 arch/x86/kernel/smp.c:257
 </IRQ>
 <TASK>
 asm_sysvec_call_function+0x1a/0x20 arch/x86/include/asm/idtentry.h:710
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200
Code: be b0 01 00 00 e8 a0 ff ff ff 31 c0 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 94 54 79 7e 65 8b 05 95 54 79 7e a9 00 01
RSP: 0018:ffffc9000331f3e8 EFLAGS: 00000283
RAX: dffffc0000000000 RBX: ffffc9000331f470 RCX: ffffffff813cf026
RDX: 1ffff92000663e90 RSI: ffffffff813cf082 RDI: ffffc9000331f480
RBP: ffffc9000331fcd0 R08: 0000000000000004 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90003318000
R13: ffffc90003320000 R14: 0000000000000001 R15: 0000000000000001
 on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
 unwind_next_frame+0x11af/0x23a0 arch/x86/kernel/unwind_orc.c:665
 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2252 [inline]
 slab_free mm/slub.c:4473 [inline]
 kmem_cache_free+0x12f/0x3a0 mm/slub.c:4548
 anon_vma_chain_free mm/rmap.c:147 [inline]
 unlink_anon_vmas+0x173/0x820 mm/rmap.c:421
 free_pgtables+0x33c/0x950 mm/memory.c:409
 exit_mmap+0x3c9/0xb20 mm/mmap.c:3393
 __mmput+0x12a/0x480 kernel/fork.c:1345
 mmput+0x62/0x70 kernel/fork.c:1367
 exit_mm kernel/exit.c:571 [inline]
 do_exit+0x9bf/0x2bb0 kernel/exit.c:869
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031
 get_signal+0x25fd/0x2770 kernel/signal.c:2917
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0dd5175b59
Code: Unable to access opcode bytes at 0x7f0dd5175b2f.
RSP: 002b:00007f0dd5f6a0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f0dd5305f68 RCX: 00007f0dd5175b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0dd5305f68
RBP: 00007f0dd5305f60 R08: 00007f0dd5f6a6c0 R09: 00007f0dd5f6a6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0dd5305f6c
R13: 000000000000000b R14: 00007ffd8748bdc0 R15: 00007ffd8748bea8
 </TASK>

The buggy address belongs to stack of task syz.0.36/5802
 and is located at offset 24 in frame:
 exit_mmap+0x0/0xb20 mm/mmap.c:3202

This frame has 2 objects:
 [32, 96) 'vmi'
 [128, 256) 'tlb'

The buggy address belongs to the virtual mapping at
 [ffffc90003318000, ffffc90003321000) created by:
 kernel_clone+0xfd/0x980 kernel/fork.c:2781

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888029ce3690 pfn:0x29ce3
memcg:ffff88801dd09c02
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff888029ce3690 0000000000000000 00000001ffffffff ffff88801dd09c02
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5781, tgid 5781 (syz.0.26), ts 125931643135, free_ts 125907940889
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263
 vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
 __vmalloc_area_node mm/vmalloc.c:3660 [inline]
 __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841
 alloc_thread_stack_node kernel/fork.c:313 [inline]
 dup_task_struct kernel/fork.c:1113 [inline]
 copy_process+0x2f3b/0x8de0 kernel/fork.c:2204
 kernel_clone+0xfd/0x980 kernel/fork.c:2781
 __do_sys_clone3+0x1f5/0x270 kernel/fork.c:3085
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5780 tgid 5779 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2608
 __folio_put+0x31c/0x3e0 mm/swap.c:128
 folio_put include/linux/mm.h:1479 [inline]
 free_page_and_swap_cache+0x249/0x2c0 mm/swap_state.c:308
 __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x89/0xe0 mm/mmu_gather.c:282
 rcu_do_batch kernel/rcu/tree.c:2569 [inline]
 rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2843
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffffc9000331f900: 00 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00
 ffffc9000331f980: 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00
>ffffc9000331fa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00
                                                 ^
 ffffc9000331fa80: 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00
 ffffc9000331fb00: 00 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	be b0 01 00 00       	mov    $0x1b0,%esi
   5:	e8 a0 ff ff ff       	call   0xffffffaa
   a:	31 c0                	xor    %eax,%eax
   c:	c3                   	ret
   d:	cc                   	int3
   e:	cc                   	int3
   f:	cc                   	int3
  10:	cc                   	int3
  11:	66 0f 1f 84 00 00 00 	nopw   0x0(%rax,%rax,1)
  18:	00 00
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
  27:	90                   	nop
  28:	90                   	nop
  29:	90                   	nop
* 2a:	f3 0f 1e fa          	endbr64 <-- trapping instruction
  2e:	65 48 8b 15 94 54 79 	mov    %gs:0x7e795494(%rip),%rdx        # 0x7e7954ca
  35:	7e
  36:	65 8b 05 95 54 79 7e 	mov    %gs:0x7e795495(%rip),%eax        # 0x7e7954d2
  3d:	a9                   	.byte 0xa9
  3e:	00 01                	add    %al,(%rcx)


Tested on:

commit:         786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e39145980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=47beaba1a1054668
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=138553b5980000

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
Read of size 4 at addr ffffc900032bfa50 by task syz.0.42/5811

CPU: 0 UID: 0 PID: 5811 Comm: syz.0.42 Not tainted 6.10.0-syzkaller-12246-g786c8248dbd3-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
 xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
 __napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:const_folio_flags.constprop.0+0x56/0x150 include/linux/page-flags.h:310
Code: 8b 6b 08 31 ff 83 e5 01 48 89 ee e8 84 cc ab ff 48 85 ed 0f 85 d4 00 00 00 e8 46 d1 ab ff 66 90 e8 3f d1 ab ff e8 3a d1 ab ff <48> 89 d8 5b 5d 41 5c c3 cc cc cc cc e8 29 d1 ab ff 48 89 dd 31 ff
RSP: 0018:ffffc900032bf6d0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffea00010118c0 RCX: ffffffff81deb54c
RDX: ffff8880274e8000 RSI: ffffffff81deb566 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000127
R13: ffff88802305c948 R14: ffffea00010118c0 R15: 0000000000000000
 folio_test_swapbacked include/linux/page-flags.h:534 [inline]
 folio_test_swapcache include/linux/page-flags.h:576 [inline]
 free_swap_cache mm/swap_state.c:291 [inline]
 free_pages_and_swap_cache+0x24e/0x510 mm/swap_state.c:325
 __tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu mm/mmu_gather.c:373 [inline]
 tlb_finish_mmu+0x168/0x7b0 mm/mmu_gather.c:465
 exit_mmap+0x3d1/0xb20 mm/mmap.c:3395
 __mmput+0x12a/0x480 kernel/fork.c:1345
 mmput+0x62/0x70 kernel/fork.c:1367
 exit_mm kernel/exit.c:571 [inline]
 do_exit+0x9bf/0x2bb0 kernel/exit.c:869
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031
 get_signal+0x25fd/0x2770 kernel/signal.c:2917
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6f7c575b59
Code: Unable to access opcode bytes at 0x7f6f7c575b2f.
RSP: 002b:00007f6f7d27b0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f6f7c705f68 RCX: 00007f6f7c575b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6f7c705f68
RBP: 00007f6f7c705f60 R08: 00007f6f7d27b6c0 R09: 00007f6f7d27b6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6f7c705f6c
R13: 000000000000000b R14: 00007ffd97f8d280 R15: 00007ffd97f8d368
 </TASK>

The buggy address belongs to stack of task syz.0.42/5811
 and is located at offset 24 in frame:
 exit_mmap+0x0/0xb20 mm/mmap.c:3202

This frame has 2 objects:
 [32, 96) 'vmi'
 [128, 256) 'tlb'

The buggy address belongs to the virtual mapping at
 [ffffc900032b8000, ffffc900032c1000) created by:
 kernel_clone+0xfd/0x980 kernel/fork.c:2781

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802b3e0000 pfn:0x2b3e0
memcg:ffff8880206d0182
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88802b3e0000 0000000000000000 00000001ffffffff ffff8880206d0182
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5653, tgid 5653 (syz-executor), ts 116595661744, free_ts 116458660012
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263
 vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
 __vmalloc_area_node mm/vmalloc.c:3660 [inline]
 __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841
 alloc_thread_stack_node kernel/fork.c:313 [inline]
 dup_task_struct kernel/fork.c:1113 [inline]
 copy_process+0x2f3b/0x8de0 kernel/fork.c:2204
 kernel_clone+0xfd/0x980 kernel/fork.c:2781
 __do_sys_clone+0xba/0x100 kernel/fork.c:2924
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5653 tgid 5653 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2608
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3988 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 __kmalloc_cache_node_noprof+0x173/0x350 mm/slub.c:4197
 kmalloc_node_noprof include/linux/slab.h:704 [inline]
 __get_vm_area_node+0xe1/0x2d0 mm/vmalloc.c:3109
 __vmalloc_node_range_noprof+0x276/0x1520 mm/vmalloc.c:3801
 __vmalloc_node_noprof mm/vmalloc.c:3906 [inline]
 vzalloc_noprof+0x6b/0x90 mm/vmalloc.c:3979
 alloc_counters net/ipv4/netfilter/ip_tables.c:799 [inline]
 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:821 [inline]
 get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline]
 do_ipt_get_ctl+0x6b8/0xaa0 net/ipv4/netfilter/ip_tables.c:1668
 nf_getsockopt+0x79/0xe0 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x18e/0x1e0 net/ipv4/ip_sockglue.c:1777
 tcp_getsockopt+0x9e/0x100 net/ipv4/tcp.c:4409
 do_sock_getsockopt+0x2e5/0x760 net/socket.c:2386
 __sys_getsockopt+0x1a1/0x270 net/socket.c:2415
 __do_sys_getsockopt net/socket.c:2425 [inline]
 __se_sys_getsockopt net/socket.c:2422 [inline]
 __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2422
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83

Memory state around the buggy address:
 ffffc900032bf900: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900032bf980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900032bfa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00
                                                 ^
 ffffc900032bfa80: 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00
 ffffc900032bfb00: 00 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	8b 6b 08             	mov    0x8(%rbx),%ebp
   3:	31 ff                	xor    %edi,%edi
   5:	83 e5 01             	and    $0x1,%ebp
   8:	48 89 ee             	mov    %rbp,%rsi
   b:	e8 84 cc ab ff       	call   0xffabcc94
  10:	48 85 ed             	test   %rbp,%rbp
  13:	0f 85 d4 00 00 00    	jne    0xed
  19:	e8 46 d1 ab ff       	call   0xffabd164
  1e:	66 90                	xchg   %ax,%ax
  20:	e8 3f d1 ab ff       	call   0xffabd164
  25:	e8 3a d1 ab ff       	call   0xffabd164
* 2a:	48 89 d8             	mov    %rbx,%rax <-- trapping instruction
  2d:	5b                   	pop    %rbx
  2e:	5d                   	pop    %rbp
  2f:	41 5c                	pop    %r12
  31:	c3                   	ret
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	e8 29 d1 ab ff       	call   0xffabd164
  3b:	48 89 dd             	mov    %rbx,%rbp
  3e:	31 ff                	xor    %edi,%edi


Tested on:

commit:         786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1293bca1980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=47beaba1a1054668
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11c0adad980000

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Tested-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Tested on:

commit:         786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167af1f1980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=47beaba1a1054668
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=174a58e3980000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

net/core/dev.c:5476:17: error: 'bpf_net_context' undeclared (first use in this function)


Tested on:

commit:         786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=be4129de17851dbe
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11ad573d980000

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Tested-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Tested on:

commit:         786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146f5203980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=47beaba1a1054668
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=122626e6980000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Tested-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Tested on:

commit:         c33ffdb7 Merge tag 'phy-for-6.11' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13c4d29d980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=582add3de1ac8f6
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12337145980000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com
Tested-by: syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com

Tested on:

commit:         c33ffdb7 Merge tag 'phy-for-6.11' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=108cff95980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=582add3de1ac8f6
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1462adad980000

Note: testing is done by a robot and is best-effort only.