[syzbot] [net?] UBSAN: array-index-out-of-bounds in llc_conn_state_process (2)

[syzbot] [net?] UBSAN: array-index-out-of-bounds in llc_conn_state_process (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    6d7ddd805123 Merge tag 'soc-fixes-6.9-3' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12596604980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7144b4fe7fbf5900
dashboard link: https://syzkaller.appspot.com/bug?extid=628f93722c08dc5aabe0
compiler:       gcc (Debian 12.2.0-14) 12.2.0, 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/4d60cb47fbb1/disk-6d7ddd80.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f3ff90de7db5/vmlinux-6d7ddd80.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d452970444cd/bzImage-6d7ddd80.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+628f93722c08dc5aabe0@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in net/llc/llc_conn.c:694:24
index -1 is out of range for type 'int [12][5]'
CPU: 0 PID: 15346 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-00023-g6d7ddd805123 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x110/0x150 lib/ubsan.c:429
 llc_find_offset net/llc/llc_conn.c:694 [inline]
 llc_qualify_conn_ev net/llc/llc_conn.c:401 [inline]
 llc_conn_service net/llc/llc_conn.c:366 [inline]
 llc_conn_state_process+0x1381/0x14e0 net/llc/llc_conn.c:72
 llc_process_tmr_ev net/llc/llc_c_ac.c:1445 [inline]
 llc_conn_tmr_common_cb+0x450/0x8e0 net/llc/llc_c_ac.c:1331
 call_timer_fn+0x1a0/0x610 kernel/time/timer.c:1793
 expire_timers kernel/time/timer.c:1844 [inline]
 __run_timers+0x74b/0xaf0 kernel/time/timer.c:2418
 __run_timer_base kernel/time/timer.c:2429 [inline]
 __run_timer_base kernel/time/timer.c:2422 [inline]
 run_timer_base+0x111/0x190 kernel/time/timer.c:2438
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2448
 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:lock_acquire+0x1f2/0x560 kernel/locking/lockdep.c:5722
Code: c1 05 0a 93 96 7e 83 f8 01 0f 85 ea 02 00 00 9c 58 f6 c4 02 0f 85 d5 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24
RSP: 0018:ffffc900033df5e0 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff9200067bebe RCX: ffffffff816b01de
RDX: 0000000000000001 RSI: ffffffff8b0cb100 RDI: ffffffff8b6f57a0
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff27bba45
R10: ffffffff93ddd22f R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff888073a52d80 R15: 0000000000000000
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
 __unix_dgram_recvmsg+0x267/0x1000 net/unix/af_unix.c:2426
 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2531
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 ____sys_recvmsg+0x5fe/0x6b0 net/socket.c:2801
 ___sys_recvmsg+0x115/0x1a0 net/socket.c:2845
 do_recvmmsg+0x2ba/0x750 net/socket.c:2939
 __sys_recvmmsg net/socket.c:3018 [inline]
 __do_sys_recvmmsg net/socket.c:3041 [inline]
 __se_sys_recvmmsg net/socket.c:3034 [inline]
 __x64_sys_recvmmsg+0x239/0x290 net/socket.c:3034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6eefa7dd69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6ef08350c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f6eefbac050 RCX: 00007f6eefa7dd69
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007f6eefaca49e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f6eefbac050 R15: 00007ffeec7fdc18
 </TASK>
---[ end trace ]---
----------------
Code disassembly (best guess):
   0:	c1 05 0a 93 96 7e 83 	roll   $0x83,0x7e96930a(%rip)        # 0x7e969311
   7:	f8                   	clc
   8:	01 0f                	add    %ecx,(%rdi)
   a:	85 ea                	test   %ebp,%edx
   c:	02 00                	add    (%rax),%al
   e:	00 9c 58 f6 c4 02 0f 	add    %bl,0xf02c4f6(%rax,%rbx,2)
  15:	85 d5                	test   %edx,%ebp
  17:	02 00                	add    (%rax),%al
  19:	00 48 85             	add    %cl,-0x7b(%rax)
  1c:	ed                   	in     (%dx),%eax
  1d:	74 01                	je     0x20
  1f:	fb                   	sti
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	48 01 c3             	add    %rax,%rbx <-- trapping instruction
  2d:	48 c7 03 00 00 00 00 	movq   $0x0,(%rbx)
  34:	48 c7 43 08 00 00 00 	movq   $0x0,0x8(%rbx)
  3b:	00
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	84                   	.byte 0x84
  3f:	24                   	.byte 0x24


---
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Re: [syzbot] [net?] UBSAN: array-index-out-of-bounds in llc_conn_state_process (2)

[Kees Cook]

On Mon, Jun 03, 2024 at 08:59:20AM -0700, syzbot wrote:
> HEAD commit:    6d7ddd805123 Merge tag 'soc-fixes-6.9-3' of git://git.kern..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12596604980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=7144b4fe7fbf5900
> dashboard link: https://syzkaller.appspot.com/bug?extid=628f93722c08dc5aabe0
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, 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/4d60cb47fbb1/disk-6d7ddd80.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/f3ff90de7db5/vmlinux-6d7ddd80.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/d452970444cd/bzImage-6d7ddd80.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+628f93722c08dc5aabe0@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> UBSAN: array-index-out-of-bounds in net/llc/llc_conn.c:694:24
> index -1 is out of range for type 'int [12][5]'
> CPU: 0 PID: 15346 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-00023-g6d7ddd805123 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
> Call Trace:
>  <IRQ>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
>  ubsan_epilogue lib/ubsan.c:231 [inline]
>  __ubsan_handle_out_of_bounds+0x110/0x150 lib/ubsan.c:429
>  llc_find_offset net/llc/llc_conn.c:694 [inline]

static int llc_find_offset(int state, int ev_type)
...
                rc = llc_offset_table[state][3]; break;

But this seems to be racing against:

>  llc_qualify_conn_ev net/llc/llc_conn.c:401 [inline]

static const struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
                                                              struct sk_buff *skb)
...
        struct llc_conn_state *curr_state =
                                        &llc_conn_state_table[llc->state - 1]; // <<<<<<
...
        for (next_trans = curr_state->transitions +
                llc_find_offset(llc->state - 1, ev->type);

Otherwise the first one would have crashed too (a -1 array index). Is
something racing:

void llc_sk_free(struct sock *sk)
...
        llc->state = LLC_CONN_OUT_OF_SVC;	// = 0
        /* Stop all (possibly) running timers */
        llc_sk_stop_all_timers(sk, true);


>  llc_conn_service net/llc/llc_conn.c:366 [inline]
>  llc_conn_state_process+0x1381/0x14e0 net/llc/llc_conn.c:72
>  llc_process_tmr_ev net/llc/llc_c_ac.c:1445 [inline]
>  llc_conn_tmr_common_cb+0x450/0x8e0 net/llc/llc_c_ac.c:1331
>  call_timer_fn+0x1a0/0x610 kernel/time/timer.c:1793
>  expire_timers kernel/time/timer.c:1844 [inline]

Given this is in a timer, it seems likely, especially given the above
"llc_sk_stop_all_timer()" call. And llc_conn_tmr_common_cb() is reachable
from several timers:

void llc_conn_pf_cycle_tmr_cb(struct timer_list *t)
{
        struct llc_sock *llc = from_timer(llc, t, pf_cycle_timer.timer);

        llc_conn_tmr_common_cb(&llc->sk, LLC_CONN_EV_TYPE_P_TMR);
}

void llc_conn_busy_tmr_cb(struct timer_list *t)
{
        struct llc_sock *llc = from_timer(llc, t, busy_state_timer.timer);

        llc_conn_tmr_common_cb(&llc->sk, LLC_CONN_EV_TYPE_BUSY_TMR);
}

void llc_conn_ack_tmr_cb(struct timer_list *t)
{
        struct llc_sock *llc = from_timer(llc, t, ack_timer.timer);

        llc_conn_tmr_common_cb(&llc->sk, LLC_CONN_EV_TYPE_ACK_TMR);
}

void llc_conn_rej_tmr_cb(struct timer_list *t)
{
        struct llc_sock *llc = from_timer(llc, t, rej_sent_timer.timer);

        llc_conn_tmr_common_cb(&llc->sk, LLC_CONN_EV_TYPE_REJ_TMR);
}

llc_ui_release() does:

        sock_put(sk);
        sock_orphan(sk);
        sock->sk = NULL;
        llc_sk_free(sk);

And I see llc_sk_free() also does:

	sock_put(sk);

What holds locking on llc? The timer callback is locking itself, but I
don't see any locks in llc_sk_free(), but in theory there should be no
locks left?

What's supposed to be happening here? Moving the state assignment later
doesn't look right, given the explicit check here:

static void llc_process_tmr_ev(struct sock *sk, struct sk_buff *skb)
{
        if (llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC) {
                printk(KERN_WARNING "%s: timer called on closed connection\n",
                       __func__);
                kfree_skb(skb);

Is it just that a lock is missing in llc_sk_free?

diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index 5c0ac243b248..99c4f06477eb 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -974,7 +974,9 @@ void llc_sk_free(struct sock *sk)
 {
 	struct llc_sock *llc = llc_sk(sk);
 
+	bh_lock_sock(sk);
 	llc->state = LLC_CONN_OUT_OF_SVC;
+	bh_unlock_sock(sk);
 	/* Stop all (possibly) running timers */
 	llc_sk_stop_all_timers(sk, true);
 #ifdef DEBUG_LLC_CONN_ALLOC

-- 
Kees Cook

Re: [syzbot] [net?] UBSAN: array-index-out-of-bounds in llc_conn_state_process (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    f1b8fa82cab7 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1092e379580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
dashboard link: https://syzkaller.appspot.com/bug?extid=628f93722c08dc5aabe0
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14407e25580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1492e379580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/932d85a2bda2/disk-f1b8fa82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5b6b8fb76e8d/vmlinux-f1b8fa82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c246b61ee396/Image-f1b8fa82.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+628f93722c08dc5aabe0@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: global-out-of-bounds in llc_qualify_conn_ev net/llc/llc_conn.c:394 [inline]
BUG: KASAN: global-out-of-bounds in llc_conn_service net/llc/llc_conn.c:360 [inline]
BUG: KASAN: global-out-of-bounds in llc_conn_state_process+0xe0/0x115c net/llc/llc_conn.c:66
Read of size 8 at addr ffff800089e50078 by task syz.0.17/4975

CPU: 1 UID: 0 PID: 4975 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 llc_qualify_conn_ev net/llc/llc_conn.c:394 [inline]
 llc_conn_service net/llc/llc_conn.c:360 [inline]
 llc_conn_state_process+0xe0/0x115c net/llc/llc_conn.c:66
 llc_conn_rcv net/llc/llc_conn.c:750 [inline]
 llc_conn_handler+0x560/0xca4 net/llc/llc_conn.c:817
 llc_rcv+0x580/0xaa0 net/llc/llc_input.c:206
 __netif_receive_skb_list_ptype net/core/dev.c:6264 [inline]
 __netif_receive_skb_list_core+0x60c/0x67c net/core/dev.c:6306
 __netif_receive_skb_list net/core/dev.c:6358 [inline]
 netif_receive_skb_list_internal+0x748/0xa0c net/core/dev.c:6449
 netif_receive_skb_list+0x70/0x818 net/core/dev.c:6501
 xdp_recv_frames net/bpf/test_run.c:268 [inline]
 xdp_test_run_batch net/bpf/test_run.c:349 [inline]
 bpf_test_run_xdp_live+0x1434/0x1770 net/bpf/test_run.c:378
 bpf_prog_test_run_xdp+0x634/0xe0c net/bpf/test_run.c:1463
 bpf_prog_test_run+0x1e0/0x250 kernel/bpf/syscall.c:4859
 __sys_bpf+0x6bc/0x82c kernel/bpf/syscall.c:6436
 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6534 [inline]
 __arm64_sys_bpf+0xd0/0xec kernel/bpf/syscall.c:6534
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

The buggy address belongs to the variable:
 llc_temp_state_transitions+0x58/0x60

The buggy address belongs to a vmalloc virtual mapping
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21c450
flags: 0x5ffc00000002000(reserved|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000002000 fffffdffc7711408 fffffdffc7711408 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff800089e4ff00: 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9
 ffff800089e4ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9
>ffff800089e50000: f9 f9 f9 f9 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9
                                                                ^
 ffff800089e50080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff800089e50100: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
==================================================================
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in net/llc/llc_conn.c:681:8
index -1 is out of range for type 'int[12][5]'
CPU: 1 UID: 0 PID: 4975 Comm: syz.0.17 Tainted: G    B               syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 ubsan_epilogue+0x14/0x48 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xd0/0xf8 lib/ubsan.c:455
 llc_find_offset net/llc/llc_conn.c:681 [inline]
 llc_qualify_conn_ev net/llc/llc_conn.c:395 [inline]
 llc_conn_service net/llc/llc_conn.c:360 [inline]
 llc_conn_state_process+0xf64/0x115c net/llc/llc_conn.c:66
 llc_conn_rcv net/llc/llc_conn.c:750 [inline]
 llc_conn_handler+0x560/0xca4 net/llc/llc_conn.c:817
 llc_rcv+0x580/0xaa0 net/llc/llc_input.c:206
 __netif_receive_skb_list_ptype net/core/dev.c:6264 [inline]
 __netif_receive_skb_list_core+0x60c/0x67c net/core/dev.c:6306
 __netif_receive_skb_list net/core/dev.c:6358 [inline]
 netif_receive_skb_list_internal+0x748/0xa0c net/core/dev.c:6449
 netif_receive_skb_list+0x70/0x818 net/core/dev.c:6501
 xdp_recv_frames net/bpf/test_run.c:268 [inline]
 xdp_test_run_batch net/bpf/test_run.c:349 [inline]
 bpf_test_run_xdp_live+0x1434/0x1770 net/bpf/test_run.c:378
 bpf_prog_test_run_xdp+0x634/0xe0c net/bpf/test_run.c:1463
 bpf_prog_test_run+0x1e0/0x250 kernel/bpf/syscall.c:4859
 __sys_bpf+0x6bc/0x82c kernel/bpf/syscall.c:6436
 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6534 [inline]
 __arm64_sys_bpf+0xd0/0xec kernel/bpf/syscall.c:6534
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
---[ end trace ]---
Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 4975 Comm: syz.0.17 Tainted: G    B               syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 03400005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : llc_qualify_conn_ev net/llc/llc_conn.c:396 [inline]
pc : llc_conn_service net/llc/llc_conn.c:360 [inline]
pc : llc_conn_state_process+0x260/0x115c net/llc/llc_conn.c:66
lr : llc_find_offset net/llc/llc_conn.c:681 [inline]
lr : llc_qualify_conn_ev net/llc/llc_conn.c:395 [inline]
lr : llc_conn_service net/llc/llc_conn.c:360 [inline]
lr : llc_conn_state_process+0x194/0x115c net/llc/llc_conn.c:66
sp : ffff800096017020
x29: ffff800096017040 x28: ffff0000ed434000 x27: ffff0000c735702e
x26: dfff800000000000 x25: dfff800000000000 x24: 0000000000000000
x23: 0000000000000004 x22: 0000000000000000 x21: ffff0000ed434000
x20: ffff0000c7357028 x19: ffff0000c7357000 x18: 00000000ffffffff
x17: 3d3d3d3d3d3d3d3d x16: 0000000000000001 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000004
x11: ffff700011467668 x10: ffff700011467668 x9 : ffff80008e879940
x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffff80008048c60c
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000020
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 llc_qualify_conn_ev net/llc/llc_conn.c:396 [inline] (P)
 llc_conn_service net/llc/llc_conn.c:360 [inline] (P)
 llc_conn_state_process+0x260/0x115c net/llc/llc_conn.c:66 (P)
 llc_conn_rcv net/llc/llc_conn.c:750 [inline]
 llc_conn_handler+0x560/0xca4 net/llc/llc_conn.c:817
 llc_rcv+0x580/0xaa0 net/llc/llc_input.c:206
 __netif_receive_skb_list_ptype net/core/dev.c:6264 [inline]
 __netif_receive_skb_list_core+0x60c/0x67c net/core/dev.c:6306
 __netif_receive_skb_list net/core/dev.c:6358 [inline]
 netif_receive_skb_list_internal+0x748/0xa0c net/core/dev.c:6449
 netif_receive_skb_list+0x70/0x818 net/core/dev.c:6501
 xdp_recv_frames net/bpf/test_run.c:268 [inline]
 xdp_test_run_batch net/bpf/test_run.c:349 [inline]
 bpf_test_run_xdp_live+0x1434/0x1770 net/bpf/test_run.c:378
 bpf_prog_test_run_xdp+0x634/0xe0c net/bpf/test_run.c:1463
 bpf_prog_test_run+0x1e0/0x250 kernel/bpf/syscall.c:4859
 __sys_bpf+0x6bc/0x82c kernel/bpf/syscall.c:6436
 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6534 [inline]
 __arm64_sys_bpf+0xd0/0xec kernel/bpf/syscall.c:6534
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Code: 35006148 b94002c8 8b28cf16 d343fec8 (387a6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	35006148 	cbnz	w8, 0xc28
   4:	b94002c8 	ldr	w8, [x22]
   8:	8b28cf16 	add	x22, x24, w8, sxtw #3
   c:	d343fec8 	lsr	x8, x22, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction


---
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