[syzbot] [batman?] WARNING in batadv_iv_ogm_process_per_outif

[syzbot] [batman?] WARNING in batadv_iv_ogm_process_per_outif

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    50d05c7c76c9 Merge tag 'landlock-7.3-rc3' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170ef749580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e
dashboard link: https://syzkaller.appspot.com/bug?extid=a079f084653164a652d1
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=108ef749580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16b696f9580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/daf497619736/disk-50d05c7c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/748fbd82f647/vmlinux-50d05c7c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e61c59099d07/bzImage-50d05c7c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com

RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
------------[ cut here ]------------
!orig_ifinfo
WARNING: net/batman-adv/bat_iv_ogm.c:1413 at batadv_iv_ogm_update_seqnos net/batman-adv/bat_iv_ogm.c:1413 [inline], CPU#1: syz.1.17/5794
WARNING: net/batman-adv/bat_iv_ogm.c:1413 at batadv_iv_ogm_process_per_outif+0x1fe4/0x25c0 net/batman-adv/bat_iv_ogm.c:1550, CPU#1: syz.1.17/5794
Modules linked in:
CPU: 1 UID: 0 PID: 5794 Comm: syz.1.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:batadv_iv_ogm_update_seqnos net/batman-adv/bat_iv_ogm.c:1413 [inline]
RIP: 0010:batadv_iv_ogm_process_per_outif+0x1fe4/0x25c0 net/batman-adv/bat_iv_ogm.c:1550
Code: ff ff e8 af ad 1c f6 49 bc 00 00 00 00 00 fc ff df e9 80 f4 ff ff e8 9b ad 1c f6 90 0f 0b 90 e9 47 e1 ff ff e8 8d ad 1c f6 90 <0f> 0b 90 48 8b bc 24 80 00 00 00 e8 6c df ff ff 48 c7 44 24 50 00
RSP: 0018:ffffc900030e7280 EFLAGS: 00010293
RAX: ffffffff8bab1d03 RBX: ffff888078df0a00 RCX: ffff88802efc3e80
RDX: 0000000000000000 RSI: ffffffff8e475f59 RDI: ffffffff8c6d9a80
RBP: ffffc900030e7410 R08: ffffffff907a2b7f R09: 1ffffffff20f456f
R10: dffffc0000000000 R11: fffffbfff20f4570 R12: dffffc0000000000
R13: 0000000002020000 R14: ffff88802bce4000 R15: ffff888078df0a00
FS:  0000000000000000(0000) GS:ffff888124dd2000(0063) knlGS:000000005807c480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7153200 CR3: 000000007a636000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 batadv_iv_ogm_process net/batman-adv/bat_iv_ogm.c:1866 [inline]
 batadv_iv_ogm_receive+0xc13/0x1740 net/batman-adv/bat_iv_ogm.c:1974
 batadv_batman_skb_recv+0x4b6/0x870 net/batman-adv/main.c:529
 __netif_receive_skb_one_core net/core/dev.c:6264 [inline]
 __netif_receive_skb net/core/dev.c:6377 [inline]
 netif_receive_skb_internal net/core/dev.c:6463 [inline]
 netif_receive_skb+0x4af/0xbf0 net/core/dev.c:6522
 tun_rx_batched+0x1de/0x790 drivers/net/tun.c:1571
 tun_get_user+0x2be0/0x44d0 drivers/net/tun.c:2045
 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2091
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x27a/0x6a0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f480ec
Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8
RSP: 002b:00000000f752fa5c EFLAGS: 00000206 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000800
RDX: 0000000000000026 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	85 d2                	test   %edx,%edx
   3:	74 0a                	je     0xf
   5:	89 ce                	mov    %ecx,%esi
   7:	81 e6 ff 0f 00 00    	and    $0xfff,%esi
   d:	89 32                	mov    %esi,(%rdx)
   f:	85 c0                	test   %eax,%eax
  11:	74 05                	je     0x18
  13:	c1 e9 0c             	shr    $0xc,%ecx
  16:	89 08                	mov    %ecx,(%rax)
  18:	31 c0                	xor    %eax,%eax
  1a:	5e                   	pop    %rsi
  1b:	5d                   	pop    %rbp
  1c:	c3                   	ret
  1d:	90                   	nop
  1e:	0f 1f 00             	nopl   (%rax)
  21:	51                   	push   %rcx
  22:	52                   	push   %rdx
  23:	55                   	push   %rbp
  24:	89 e5                	mov    %esp,%ebp
  26:	0f 34                	sysenter
  28:	cd 80                	int    $0x80
* 2a:	5d                   	pop    %rbp <-- trapping instruction
  2b:	5a                   	pop    %rdx
  2c:	59                   	pop    %rcx
  2d:	c3                   	ret
  2e:	90                   	nop
  2f:	90                   	nop
  30:	90                   	nop
  31:	90                   	nop
  32:	90                   	nop
  33:	90                   	nop
  34:	90                   	nop
  35:	90                   	nop
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	58                   	pop    %rax
  3f:	b8                   	.byte 0xb8


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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Forwarded: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure
Author: kartikey406@gmail.com

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



batadv_orig_ifinfo_new() returns NULL only when its GFP_ATOMIC
allocation fails, which is a normal runtime condition and not a bug.
batadv_v_ogm_forward() already handles this the same way, simply
checking for NULL without a WARN_ON.

Do the same in batadv_iv_ogm_update_seqnos() to avoid a spurious
WARN_ON splat when the allocation fails (e.g. under fault injection).

Fixes: 7351a4822d42 ("batman-adv: split out router from orig_node")
Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a079f084653164a652d1
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 net/batman-adv/bat_iv_ogm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8f4f..d8a6a0f64ce2 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,7 +1410,7 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	if (!orig_ifinfo) {
 		batadv_orig_node_put(orig_node);
 		return 0;
 	}
-- 
2.43.0

Forwarded: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure

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linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

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Subject: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure
Author: kartikey406@gmail.com

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



batadv_orig_ifinfo_new() returns NULL only when its GFP_ATOMIC
allocation fails, which is a normal runtime condition and not a bug.
batadv_v_ogm_forward() already handles this the same way, simply
checking for NULL without a WARN_ON.

Do the same in batadv_iv_ogm_update_seqnos() to avoid a spurious
WARN_ON splat when the allocation fails (e.g. under fault injection).

Fixes: 7351a4822d42 ("batman-adv: split out router from orig_node")
Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a079f084653164a652d1
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 net/batman-adv/bat_iv_ogm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8f4f..d8a6a0f64ce2 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,7 +1410,7 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	if (!orig_ifinfo) {
 		batadv_orig_node_put(orig_node);
 		return 0;
 	}
-- 
2.43.0

Forwarded: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] batman-adv: avoid WARN_ON for orig_ifinfo allocation failure
Author: kartikey406@gmail.com

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



batadv_orig_ifinfo_new() returns NULL only when its GFP_ATOMIC
allocation fails, which is a normal runtime condition and not a bug.
batadv_v_ogm_forward() already handles this the same way, simply
checking for NULL without a WARN_ON.

Do the same in batadv_iv_ogm_update_seqnos() to avoid a spurious
WARN_ON splat when the allocation fails (e.g. under fault injection).

Fixes: 7351a4822d42 ("batman-adv: split out router from orig_node")
Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a079f084653164a652d1
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 net/batman-adv/bat_iv_ogm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8f4f..d8a6a0f64ce2 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,7 +1410,7 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	if (!orig_ifinfo) {
 		batadv_orig_node_put(orig_node);
 		return 0;
 	}
-- 
2.43.0

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

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linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c96b90462f24debacca971d2e86713

Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8..3c5f7c80b 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,9 +1410,12 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	/* batadv_orig_ifinfo_new() can fail when the memory allocation fails.
+	 * This is not a bug, so don't warn and treat the OGM as non-duplicate.
+	 */
+	if (!orig_ifinfo) {
 		batadv_orig_node_put(orig_node);
-		return 0;
+		return BATADV_NO_DUP;
 	}
 
 	spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

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

Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8..3c5f7c80b 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,9 +1410,12 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	/* batadv_orig_ifinfo_new() can fail when the memory allocation fails.
+	 * This is not a bug, so don't warn and treat the OGM as non-duplicate.
+	 */
+	if (!orig_ifinfo) {
 		batadv_orig_node_put(orig_node);
-		return 0;
+		return BATADV_NO_DUP;
 	}
 
 	spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);

Forwarded: [PATCH] WARNING in batadv_iv_ogm_process_per_outif

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linux-kernel@vger.kernel.org.

***

Subject: [PATCH] WARNING in batadv_iv_ogm_process_per_outif
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c96b90462f24debacca971d2e86713

Reported-by: syzbot+a079f084653164a652d1@syzkaller.appspotmail.com

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 53fbdbbe8..24ea350cd 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1410,9 +1410,13 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
 		return BATADV_NO_DUP;
 
 	orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
-	if (WARN_ON(!orig_ifinfo)) {
+	if (!orig_ifinfo) {
+		/* The GFP_ATOMIC allocation inside batadv_orig_ifinfo_new()
+		 * may fail under memory pressure. That is not a kernel bug,
+		 * so don't WARN; just skip duplicate detection.
+		 */
 		batadv_orig_node_put(orig_node);
-		return 0;
+		return BATADV_NO_DUP;
 	}
 
 	spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);

[syzbot] [raid?] UBSAN: array-index-out-of-bounds in super_90_sync

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    893e11787f78 Merge tag 'x86_urgent_for_7.3-rc3' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11af7af9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
dashboard link: https://syzkaller.appspot.com/bug?extid=9e3014263a35700ab49b
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7d6d05cecce7/disk-893e1178.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f4fa34852d36/vmlinux-893e1178.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a45af623528/bzImage-893e1178.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9e3014263a35700ab49b@syzkaller.appspotmail.com

md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in drivers/md/md.c:1697:17
index 124 is out of range for type 'mdp_disk_t [27]'
CPU: 1 UID: 0 PID: 10197 Comm: syz.3.1362 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455
 super_90_sync+0x1eed/0x1ff0 drivers/md/md.c:1697
 sync_super drivers/md/md.c:2505 [inline]
 sync_sbs drivers/md/md.c:2747 [inline]
 md_update_sb+0xbba/0x2840 drivers/md/md.c:2923
 state_store+0x31e/0x1340 drivers/md/md.c:3245
 rdev_attr_store+0x465/0x560 drivers/md/md.c:3768
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f977e59e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f977f3cb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f977e825fa0 RCX: 00007f977e59e159
RDX: 000000000000000b RSI: 0000200000000a00 RDI: 0000000000000006
RBP: 00007f977e63503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f977e826038 R14: 00007f977e825fa0 R15: 00007ffef91f5d68
 </TASK>
---[ end trace ]---


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

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

Reported-by: syzbot+9e3014263a35700ab49b@syzkaller.appspotmail.com

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 680b34a63..bcc32b83c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1393,7 +1393,11 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
 		goto abort;
 	}
 
-	if (sb->raid_disks <= 0)
+	/*
+	 * sb->disks[] has only MD_SB_DISKS entries.  A larger raid_disks
+	 * count would later make super_90_sync() index past that array.
+	 */
+	if (sb->raid_disks <= 0 || sb->raid_disks > MD_SB_DISKS)
 		goto abort;
 
 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
@@ -1607,6 +1611,18 @@ static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
 	struct md_rdev *rdev2;
 	int next_spare = mddev->raid_disks;
 
+	/*
+	 * A 0.90 superblock has a fixed-size mdp_disk_t array and uses
+	 * raid_disks as both a loop bound and the first spare disk slot.
+	 * Never index sb->disks[] if an invalid raid_disks value reached
+	 * us through any configuration path.
+	 */
+	if (mddev->raid_disks < 0 || mddev->raid_disks > MD_SB_DISKS) {
+		pr_warn("md: %s: invalid raid_disks %d for 0.90 metadata\n",
+			mdname(mddev), mddev->raid_disks);
+		return;
+	}
+
 	/* make rdev->sb match mddev data..
 	 *
 	 * 1/ zero out disks
@@ -4448,8 +4464,19 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
 		mddev->delta_disks = n - olddisks;
 		mddev->raid_disks = n;
 		mddev->reshape_backwards = (mddev->delta_disks < 0);
-	} else
-		mddev->raid_disks = n;
+	} else {
+		/*
+		 * 0.90 metadata only has room for MD_SB_DISKS descriptors.
+		 * Larger values would make super_90_sync() index beyond
+		 * sb->disks[].
+		 */
+		if ((mddev->persistent && mddev->major_version == 0 &&
+		     n > MD_SB_DISKS) ||
+		    (mddev->max_disks && n > mddev->max_disks))
+			err = -EINVAL;
+		else
+			mddev->raid_disks = n;
+	}
 out_unlock:
 	memalloc_noio_restore(noio_flags);
 	mddev_unlock_and_resume(mddev);
@@ -7926,6 +7953,18 @@ int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info)
 		mddev->ctime         = ktime_get_real_seconds();
 		return 0;
 	}
+
+	/*
+	 * Persistent 0.90 metadata stores disks in sb->disks[MD_SB_DISKS].
+	 * A larger raid_disks count would make super_90_sync() index past
+	 * that array; non-persistent arrays have no such on-disk limit.
+	 */
+	if (info->raid_disks < 0 ||
+	    (!info->not_persistent && info->raid_disks > MD_SB_DISKS)) {
+		pr_warn("md: invalid raid_disks %d\n", info->raid_disks);
+		return -EINVAL;
+	}
+
 	mddev->major_version = MD_MAJOR_VERSION;
 	mddev->minor_version = MD_MINOR_VERSION;
 	mddev->patch_version = MD_PATCHLEVEL_VERSION;

[syzbot] [kernel?] BUG: unable to handle kernel paging request in cirrus_primary_plane_helper_atomic_update

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3eb40771c00a Merge tag 'soc-fixes-7.2-3' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13949949580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1d67342c314f228d
dashboard link: https://syzkaller.appspot.com/bug?extid=2442951a6abb004df963
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10d696c6580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2442951a6abb004df963@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffc900030a7000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 1c000067 P4D 1c000067 PUD 1d6a8067 PMD 25dcb067 PTE 0

Oops: Oops: 0002 [#1] SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 5985 Comm: syz-executor238 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:rep_movs arch/x86/lib/iomem.c:13 [inline]
RIP: 0010:string_memcpy_toio arch/x86/lib/iomem.c:64 [inline]
RIP: 0010:memcpy_toio+0x87/0xe0 arch/x86/lib/iomem.c:110
Code: b6 fc 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 70 3f b6 fc 4d 85 ed 75 33 e8 c6 44 b6 fc 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5 40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 e8 a3 44 b6 fc
RSP: 0018:ffffc900036ef4f0 EFLAGS: 00010206

RAX: 0000000000000000 RBX: ffffc900030a6d20 RCX: 00000000000000d8
RDX: ffff88802dc8a540 RSI: ffffc90003c31f60 RDI: ffffc900030a7000
RBP: 0000000000000640 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90003c31c80
R13: 0000000000000000 R14: ffffc900030a6d20 R15: 0000000000000640
FS:  0000000000000000(0000) GS:ffff8880d5ede000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900030a7000 CR3: 000000003cd11000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 iosys_map_memcpy_to include/linux/iosys-map.h:285 [inline]
 drm_fb_memcpy+0x459/0x620 drivers/gpu/drm/drm_format_helper.c:442
 cirrus_primary_plane_helper_atomic_update+0xb1d/0xfe0 drivers/gpu/drm/tiny/cirrus-qemu.c:358
 drm_atomic_helper_commit_planes+0x497/0xf10 drivers/gpu/drm/drm_atomic_helper.c:3038
 drm_atomic_helper_commit_tail+0x7f/0x130 drivers/gpu/drm/drm_atomic_helper.c:1989
 commit_tail+0x338/0x430 drivers/gpu/drm/drm_atomic_helper.c:2074
 drm_atomic_helper_commit+0x303/0x380 drivers/gpu/drm/drm_atomic_helper.c:2312
 drm_atomic_commit+0x230/0x300 drivers/gpu/drm/drm_atomic.c:1789
 drm_client_modeset_commit_atomic+0x6a6/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1104
 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1207
 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1233
 __drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x137/0x160 drivers/gpu/drm/drm_fb_helper.c:138
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:126 [inline]
 drm_fb_helper_restore_fbdev_mode_unlocked+0x93/0xc0 drivers/gpu/drm/drm_fb_helper.c:169
 drm_fbdev_client_restore+0x1b/0x30 drivers/gpu/drm/clients/drm_fbdev_client.c:45
 drm_client_dev_restore+0x205/0x2a0 drivers/gpu/drm/drm_client_event.c:118
 drm_lastclose drivers/gpu/drm/drm_file.c:408 [inline]
 drm_release+0x2c6/0x360 drivers/gpu/drm/drm_file.c:441
 __fput+0x3ff/0xb50 fs/file_table.c:512
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2ae0 kernel/exit.c:1009
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 __do_sys_exit_group kernel/exit.c:1163 [inline]
 __se_sys_exit_group kernel/exit.c:1161 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1161
 x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6d6a4b3905
Code: Unable to access opcode bytes at 0x7f6d6a4b38db.
RSP: 002b:00007ffd867f5c08 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f6d6a4b3905
RDX: 00000000000000e7 RSI: ffffffffffffffd8 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001
R13: 00007f6d6a548100 R14: 00007f6d6a54a388 R15: 00007f6d6a54a3a0
 </TASK>
Modules linked in:
CR2: ffffc900030a7000
---[ end trace 0000000000000000 ]---
RIP: 0010:rep_movs arch/x86/lib/iomem.c:13 [inline]
RIP: 0010:string_memcpy_toio arch/x86/lib/iomem.c:64 [inline]
RIP: 0010:memcpy_toio+0x87/0xe0 arch/x86/lib/iomem.c:110
Code: b6 fc 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 70 3f b6 fc 4d 85 ed 75 33 e8 c6 44 b6 fc 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5 40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 e8 a3 44 b6 fc
RSP: 0018:ffffc900036ef4f0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffffc900030a6d20 RCX: 00000000000000d8
RDX: ffff88802dc8a540 RSI: ffffc90003c31f60 RDI: ffffc900030a7000
RBP: 0000000000000640 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90003c31c80
R13: 0000000000000000 R14: ffffc900030a6d20 R15: 0000000000000640
FS:  0000000000000000(0000) GS:ffff8880d5ede000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900030a7000 CR3: 000000003cd11000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	b6 fc                	mov    $0xfc,%dh
   2:	49 89 dd             	mov    %rbx,%r13
   5:	31 ff                	xor    %edi,%edi
   7:	41 83 e5 02          	and    $0x2,%r13d
   b:	4c 89 ee             	mov    %r13,%rsi
   e:	e8 70 3f b6 fc       	call   0xfcb63f83
  13:	4d 85 ed             	test   %r13,%r13
  16:	75 33                	jne    0x4b
  18:	e8 c6 44 b6 fc       	call   0xfcb644e3
  1d:	48 89 e9             	mov    %rbp,%rcx
  20:	48 89 df             	mov    %rbx,%rdi
  23:	4c 89 e6             	mov    %r12,%rsi
  26:	48 c1 e9 02          	shr    $0x2,%rcx
* 2a:	f3 a5                	rep movsl %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2c:	40 f6 c5 02          	test   $0x2,%bpl
  30:	74 02                	je     0x34
  32:	66 a5                	movsw  %ds:(%rsi),%es:(%rdi)
  34:	40 f6 c5 01          	test   $0x1,%bpl
  38:	74 01                	je     0x3b
  3a:	a4                   	movsb  %ds:(%rsi),%es:(%rdi)
  3b:	e8 a3 44 b6 fc       	call   0xfcb644e3


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 958f35cbb8955ca3fa439cd9f2092cb42414aa8c

Reported-by: syzbot+2442951a6abb004df963@syzkaller.appspotmail.com

diff --git a/drivers/gpu/drm/tiny/cirrus-qemu.c b/drivers/gpu/drm/tiny/cirrus-qemu.c
index 075221b43..f66e33f18 100644
--- a/drivers/gpu/drm/tiny/cirrus-qemu.c
+++ b/drivers/gpu/drm/tiny/cirrus-qemu.c
@@ -68,6 +68,7 @@ struct cirrus_device {
 
 	/* HW resources */
 	void __iomem		       *vram;
+	resource_size_t		       vram_size;
 	void __iomem		       *mmio;
 };
 
@@ -298,6 +299,7 @@ static const uint64_t cirrus_primary_plane_format_modifiers[] = {
 static int cirrus_primary_plane_helper_atomic_check(struct drm_plane *plane,
 						    struct drm_atomic_commit *state)
 {
+	struct cirrus_device *cirrus = to_cirrus(plane->dev);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_framebuffer *fb = new_plane_state->fb;
 	struct drm_crtc *new_crtc = new_plane_state->crtc;
@@ -319,7 +321,7 @@ static int cirrus_primary_plane_helper_atomic_check(struct drm_plane *plane,
 	/* validate size constraints */
 	if (fb->pitches[0] > CIRRUS_MAX_PITCH)
 		return -EINVAL;
-	else if (fb->pitches[0] > CIRRUS_VRAM_SIZE / fb->height)
+	else if (fb->pitches[0] > cirrus->vram_size / fb->height)
 		return -EINVAL;
 
 	return 0;
@@ -514,6 +516,7 @@ static int cirrus_pipe_init(struct cirrus_device *cirrus)
 static enum drm_mode_status cirrus_mode_config_mode_valid(struct drm_device *dev,
 							  const struct drm_display_mode *mode)
 {
+	struct cirrus_device *cirrus = to_cirrus(dev);
 	const struct drm_format_info *format = drm_format_info(DRM_FORMAT_XRGB8888);
 	u64 pitch;
 
@@ -525,7 +528,7 @@ static enum drm_mode_status cirrus_mode_config_mode_valid(struct drm_device *dev
 		return MODE_BAD_WIDTH;
 	if (pitch > CIRRUS_MAX_PITCH)
 		return MODE_BAD_WIDTH; /* maximum programmable pitch */
-	if (pitch > CIRRUS_VRAM_SIZE / mode->vdisplay)
+	if (pitch > cirrus->vram_size / mode->vdisplay)
 		return MODE_MEM;
 
 	return MODE_OK;
@@ -602,8 +605,10 @@ static int cirrus_pci_probe(struct pci_dev *pdev,
 
 	dev = &cirrus->dev;
 
+	cirrus->vram_size = min_t(resource_size_t, pci_resource_len(pdev, 0),
+				 CIRRUS_VRAM_SIZE);
 	cirrus->vram = devm_ioremap(&pdev->dev, pci_resource_start(pdev, 0),
-				    pci_resource_len(pdev, 0));
+				    cirrus->vram_size);
 	if (cirrus->vram == NULL)
 		return -ENOMEM;
 

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 958f35cbb8955ca3fa439cd9f2092cb42414aa8c

[syzbot] [block?] UBSAN: shift-out-of-bounds in null_process_zoned_cmd

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    c21bb4193868 Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1218ecc6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4e38b15c29e6a1d9
dashboard link: https://syzkaller.appspot.com/bug?extid=abd6a8dca0f2b7726060
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cf4c0f46390e/disk-c21bb419.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21802e5d4446/vmlinux-c21bb419.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c46db810c9d/bzImage-c21bb419.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+abd6a8dca0f2b7726060@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/block/null_blk/zoned.c:21:14
shift exponent -1 is negative
CPU: 0 UID: 0 PID: 5906 Comm: syz.0.14 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494
 null_zone_no drivers/block/null_blk/zoned.c:21 [inline]
 null_process_zoned_cmd+0xf76/0xf80 drivers/block/null_blk/zoned.c:728
 null_handle_cmd drivers/block/null_blk/main.c:1455 [inline]
 null_queue_rq+0x8bc/0xe70 drivers/block/null_blk/main.c:1703
 __blk_mq_issue_directly block/blk-mq.c:2694 [inline]
 blk_mq_try_issue_directly+0x3f4/0x880 block/blk-mq.c:2754
 blk_mq_submit_bio+0x20c0/0x2a40 block/blk-mq.c:3208
 __submit_bio_noacct_mq block/blk-core.c:756 [inline]
 submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:790
 bh_submit fs/buffer.c:1239 [inline]
 block_read_full_folio+0x7a6/0x810 fs/buffer.c:2463
 filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2510
 do_read_cache_folio+0x354/0x590 mm/filemap.c:4140
 read_mapping_folio include/linux/pagemap.h:1015 [inline]
 read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
 adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:357
 check_partition block/partitions/core.c:143 [inline]
 blk_add_partitions block/partitions/core.c:591 [inline]
 bdev_disk_changed+0x851/0x17a0 block/partitions/core.c:695
 blkdev_get_whole+0x372/0x510 block/bdev.c:751
 bdev_open+0x324/0xd70 block/bdev.c:960
 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1062
 disk_scan_partitions+0x1bb/0x2c0 block/genhd.c:387
 add_disk_final block/genhd.c:412 [inline]
 add_disk_fwnode+0x24b/0x3a0 block/genhd.c:606
 add_disk include/linux/blkdev.h:800 [inline]
 null_add_dev+0x130b/0x1d70 drivers/block/null_blk/main.c:2052
 nullb_device_power_store+0x240/0x380 drivers/block/null_blk/main.c:501
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f444919e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f444a0ae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4449425fa0 RCX: 00007f444919e0d9
RDX: 0000000000000002 RSI: 0000200000000700 RDI: 0000000000000004
RBP: 00007f4449235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4449426038 R14: 00007f4449425fa0 R15: 00007ffc895cc1c8
 </TASK>
---[ end trace ]---


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 069f4aad347e1f3181639d2dfbadfae592df93e7

Reported-by: syzbot+abd6a8dca0f2b7726060@syzkaller.appspotmail.com

diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index 384bdce6a..1c3ef902f 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -88,6 +88,11 @@ int null_init_zoned_dev(struct nullb_device *dev,
 	zone_capacity_sects = mb_to_sects(dev->zone_capacity);
 	dev_capacity_sects = mb_to_sects(dev->size);
 	dev->zone_size_sects = mb_to_sects(dev->zone_size);
+	if (!dev->zone_size_sects) {
+		pr_err("zone_size is too large\n");
+		return -EINVAL;
+	}
+
 	dev->nr_zones = round_up(dev_capacity_sects, dev->zone_size_sects)
 		>> ilog2(dev->zone_size_sects);
 

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 069f4aad347e1f3181639d2dfbadfae592df93e7

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 069f4aad347e1f3181639d2dfbadfae592df93e7

[syzbot] [usb?] UBSAN: array-index-out-of-bounds in uea_bind

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3708dd948844 Merge tag 'pm-7.2-rc6' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14ff71b9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=92f5bf49bf4ac75223ca
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11a0a5b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ff71b9580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3708dd94.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/57f69e2a6e3b/vmlinux-3708dd94.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3511d4246fb6/bzImage-3708dd94.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+92f5bf49bf4ac75223ca@syzkaller.appspotmail.com

usb 5-1: reset high-speed USB device number 6 using dummy_hcd
usb 5-1: device descriptor read/64, error -71
usb 5-1: reset high-speed USB device number 6 using dummy_hcd
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in drivers/usb/atm/ueagle-atm.c:2466:28
index 4 is out of range for type 'bool [4]'
CPU: 2 UID: 0 PID: 847 Comm: kworker/2:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455
 uea_bind+0x1014/0x1380 drivers/usb/atm/ueagle-atm.c:2466
 usbatm_usb_probe+0x378/0x1b50 drivers/usb/atm/usbatm.c:1058
 uea_probe+0x194/0x570 drivers/usb/atm/ueagle-atm.c:2597
 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x30a3/0x4a60 drivers/usb/core/hub.c:5953
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
---[ end trace ]---


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
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If you want to undo deduplication, reply with:
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Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 762137ff748fa0c920f82ce718163691cb02f907

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 762137ff748fa0c920f82ce718163691cb02f907

Reported-by: syzbot+92f5bf49bf4ac75223ca@syzkaller.appspotmail.com

diff --git a/drivers/usb/atm/ueagle-atm.c b/drivers/usb/atm/ueagle-atm.c
index 4266a0cb7..b1b358b3a 100644
--- a/drivers/usb/atm/ueagle-atm.c
+++ b/drivers/usb/atm/ueagle-atm.c
@@ -2458,12 +2458,21 @@ static int uea_bind(struct usbatm_data *usbatm, struct usb_interface *intf,
 	struct uea_softc *sc;
 	int ret, ifnum = intf->altsetting->desc.bInterfaceNumber;
 	unsigned int alt;
+	int modem_idx;
 
 	/* interface 0 is for firmware/monitoring */
 	if (ifnum != UEA_INTR_IFACE_NO)
 		return -ENODEV;
 
-	usbatm->flags = (sync_wait[modem_index] ? 0 : UDSL_SKIP_HEAVY_INIT);
+	/*
+	 * modem_index is a global counter that stops at NB_MODEM once that
+	 * many devices have been probed. Wrap the index the same way as
+	 * sc->modem_index below so that the module parameter lookup stays
+	 * within the bounds of the arrays.
+	 */
+	modem_idx = (modem_index < NB_MODEM) ? modem_index : 0;
+
+	usbatm->flags = (sync_wait[modem_idx] ? 0 : UDSL_SKIP_HEAVY_INIT);
 
 	/* interface 1 is for outbound traffic */
 	ret = claim_interface(usb, usbatm, UEA_US_IFACE_NO);

[syzbot] [fs?] KASAN: slab-use-after-free Write in config_item_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    fc02acf6ac0c Merge tag 'platform-drivers-x86-v7.2-4' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1220b1b9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a
dashboard link: https://syzkaller.appspot.com/bug?extid=6b16e3d085833cbf3e25
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=121ea49e580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1620b1b9580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b3bff1d63ddf/disk-fc02acf6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/04efa97b7fb6/vmlinux-fc02acf6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/be724b7ea80c/bzImage-fc02acf6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6b16e3d085833cbf3e25@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline]
BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline]
BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline]
BUG: KASAN: slab-use-after-free in kref_get include/linux/kref.h:45 [inline]
BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 fs/configfs/item.c:104
Write of size 4 at addr ffff888039f5201c by task syz.3.408/6784

CPU: 1 UID: 0 PID: 6784 Comm: syz.3.408 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
 atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
 __refcount_add include/linux/refcount.h:283 [inline]
 __refcount_inc include/linux/refcount.h:366 [inline]
 refcount_inc include/linux/refcount.h:383 [inline]
 kref_get include/linux/kref.h:45 [inline]
 config_item_get+0x26/0x90 fs/configfs/item.c:104
 configfs_get_config_item fs/configfs/configfs_internal.h:127 [inline]
 get_target fs/configfs/symlink.c:128 [inline]
 configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185
 vfs_symlink+0x18b/0x330 fs/namei.c:5660
 filename_symlinkat+0x1cd/0x420 fs/namei.c:5685
 __do_sys_symlinkat fs/namei.c:5705 [inline]
 __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5700
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f98f891de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f98f7f7e028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f98f8ba5fa0 RCX: 00007f98f891de99
RDX: 0000200000000340 RSI: ffffffffffffff9c RDI: 0000200000000300
RBP: 00007f98f89b3eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f98f8ba6038 R14: 00007f98f8ba5fa0 R15: 00007ffce9af1ce8
 </TASK>

Allocated by task 6785:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3d2/0x6b0 mm/slub.c:5489
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 afunc_alloc_inst+0x4c/0x770 drivers/usb/gadget/function/f_uac2.c:2192
 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
 usb_get_function_instance+0xe3/0x2f0 drivers/usb/gadget/functions.c:44
 function_make+0x127/0x360 drivers/usb/gadget/configfs.c:626
 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360
 vfs_mkdir+0x402/0x620 fs/namei.c:5276
 filename_mkdirat+0x289/0x520 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888039f52000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 28 bytes inside of
 freed 2048-byte region [ffff888039f52000, ffff888039f52800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888039f50000 pfn:0x39f50
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88813ffb2000 ffffea0000d6de10 ffffea0000f10610
raw: ffff888039f50000 0000000800080005 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88813ffb2000 ffffea0000d6de10 ffffea0000f10610
head: ffff888039f50000 0000000800080005 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5743, tgid 5743 (syz-executor), ts 119768577290, free_ts 119599127308
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3380
 new_slab mm/slub.c:3426 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x468/0x6b0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 batadv_hardif_add_interface net/batman-adv/hard-interface.c:878 [inline]
 batadv_hard_if_event+0x282a/0x3530 net/batman-adv/hard-interface.c:1087
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 register_netdevice+0x18c0/0x1ed0 net/core/dev.c:11484
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1070 [inline]
 nsim_create+0xbe9/0x1160 drivers/net/netdevsim/netdev.c:1152
 __nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1509
 nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1570
 nsim_drv_probe+0x8d6/0xc00 drivers/net/netdevsim/dev.c:1731
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
page last free pid 5908 tgid 5908 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x10e7/0x11c0 mm/page_alloc.c:2950
 __slab_free+0x252/0x2a0 mm/slub.c:5741
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_noprof+0x355/0x650 mm/slub.c:4931
 vm_area_alloc+0x24/0x140 mm/vma_init.c:32
 __mmap_new_vma mm/vma.c:2547 [inline]
 __mmap_region mm/vma.c:2774 [inline]
 mmap_region+0x1263/0x2310 mm/vma.c:2860
 do_mmap+0xc1e/0x10b0 mm/mmap.c:560
 vm_mmap_pgoff+0x275/0x4e0 mm/util.c:581
 ksys_mmap_pgoff+0x4a6/0x720 mm/mmap.c:606
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888039f51f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888039f51f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888039f52000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888039f52080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888039f52100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
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Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: alsowereme@outlook.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a7c1290eef60711c10289c056ad32ed1f2b47b12

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a7c1290eef60711c10289c056ad32ed1f2b47b12

Reported-by: syzbot+6b16e3d085833cbf3e25@syzkaller.appspotmail.com

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 3c88f13f1..b0812432f 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1552,12 +1552,14 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	if (sd->s_type & CONFIGFS_USET_DIR) {
 		configfs_detach_group(dentry);
+		d_drop(dentry);
 
 		mutex_lock(&subsys->su_mutex);
 		client_disconnect_notify(parent_item, item);
 		unlink_group(to_config_group(item));
 	} else {
 		configfs_detach_item(dentry);
+		d_drop(dentry);
 
 		mutex_lock(&subsys->su_mutex);
 		client_disconnect_notify(parent_item, item);

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

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Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a7c1290eef60711c10289c056ad32ed1f2b47b12

Reported-by: syzbot+6b16e3d085833cbf3e25@syzkaller.appspotmail.com

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 3c88f13f1..d9c222ff0 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -418,6 +418,16 @@ static void configfs_remove_dir(struct dentry *d)
 			pr_warn("remove_dir (%pd): attributes remain", d);
 	}
 
+	/*
+	 * The dentry can still have external references (e.g. from a
+	 * concurrent configfs_symlink() path lookup), in which case
+	 * simple_rmdir() will not have unhashed it yet.  Make sure the
+	 * dentry is unreachable before the caller drops the last
+	 * reference to the config_item, since configfs_symlink() resolves
+	 * targets by taking a reference through a hashed dentry.
+	 */
+	d_drop(d);
+
 	pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
 
 	dput(parent);

Forwarded: [PATCH] configfs: unhash dentry before dropping the item

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH] configfs: unhash dentry before dropping the item
Author: jchuang26@m.fudan.edu.cn

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a7c1290eef60711c10289c056ad32ed1f2b47b12