[syzbot] [bluetooth?] WARNING in l2cap_chan_send

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f99c5f563c17 Merge tag 'nf-24-03-21' of git://git.kernel.o..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=14f69bd3180000
kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=b6919040d9958e2fc1ae
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/65d3f3eb786e/disk-f99c5f56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/799cf7f28ff8/vmlinux-f99c5f56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ab26c60c3845/bzImage-f99c5f56.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b69190...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 8027 at kernel/workqueue.c:2322 __queue_work+0xc6a/0xec0 kernel/workqueue.c:2321
Modules linked in:
CPU: 1 PID: 8027 Comm: syz-executor.4 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__queue_work+0xc6a/0xec0 kernel/workqueue.c:2321
Code: ff e8 3a e0 35 00 eb 21 e8 33 e0 35 00 eb 1a e8 2c e0 35 00 eb 13 e8 25 e0 35 00 90 0f 0b 90 e9 74 fd ff ff e8 17 e0 35 00 90 <0f> 0b 90 48 83 c4 68 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc
RSP: 0018:ffffc9000305f4c0 EFLAGS: 00010083
RAX: ffffffff815f103d RBX: ffff888022ff3c00 RCX: 0000000000040000
RDX: ffffc90012785000 RSI: 0000000000016230 RDI: 0000000000016231
RBP: 0000000000000000 R08: ffffffff815f0513 R09: 1ffff1100d0621be
R10: dffffc0000000000 R11: ffffed100d0621bf R12: dffffc0000000000
R13: ffff88802e5ad9c0 R14: ffff88802e5ad800 R15: 0000000000000008
FS: 00007f9fcf6a96c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001300 CR3: 0000000062a38000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
queue_work_on+0x14f/0x250 kernel/workqueue.c:2435
l2cap_chan_send+0x3d6/0x2680
l2cap_sock_sendmsg+0x1b4/0x2c0 net/bluetooth/l2cap_sock.c:1139
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmmsg+0x3b2/0x740 net/socket.c:2724
__do_sys_sendmmsg net/socket.c:2753 [inline]
__se_sys_sendmmsg net/socket.c:2750 [inline]
__x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f9fce87de69
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:00007f9fcf6a90c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f9fce9abf80 RCX: 00007f9fce87de69
RDX: 00000000ffffff80 RSI: 0000000020004100 RDI: 0000000000000006
RBP: 00007f9fce8ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010040 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9fce9abf80 R15: 00007ffd6dcb5768
</TASK>


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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: a7c7074b58d2 Merge tag 'fbdev-for-7.2-rc7' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=171c0149580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b924ab49cf8bae2a
dashboard link: https://syzkaller.appspot.com/bug?extid=b6919040d9958e2fc1ae
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109c0149580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b69190...@syzkaller.appspotmail.com

------------[ cut here ]------------

workqueue: cannot queue hci_tx_work on wq hci0
WARNING: kernel/workqueue.c:2306 at __queue_work+0xd4a/0x1090 kernel/workqueue.c:2305, CPU#1: syz-executor109/5985
Modules linked in:
CPU: 1 UID: 0 PID: 5985 Comm: syz-executor109 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__queue_work+0xd66/0x1090 kernel/workqueue.c:2305
Code: 49 81 c7 70 01 00 00 4c 8d 35 86 dd 5b 0e 48 89 f8 48 c1 e8 03 80 3c 18 00 74 05 e8 a4 20 a5 00 49 8b 75 18 4c 89 f7 4c 89 fa <67> 48 0f b9 3a 4c 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8
RSP: 0018:ffffc900032d7510 EFLAGS: 00010046
RAX: 1ffff11004fd798a RBX: dffffc0000000000 RCX: ffff8880308b1f00
RDX: ffff88807d1c0970 RSI: ffffffff8a85e850 RDI: ffffffff8fe7e260
RBP: 0000000000000000 R08: ffff888027ebcc3f R09: 1ffff11004fd7987
R10: dffffc0000000000 R11: ffffed1004fd7988 R12: 0000000000000008
R13: ffff888027ebcc38 R14: ffffffff8fe7e260 R15: ffff88807d1c0970
FS: 00007fed8a7926c0(0000) GS:ffff888125866000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fed8c796d58 CR3: 00000000739ba000 CR4: 00000000003526f0
Call Trace:
<TASK>
queue_work_on+0x106/0x1c0 kernel/workqueue.c:2452
l2cap_chan_send+0x168a/0x22f0 net/bluetooth/l2cap_core.c:-1
l2cap_sock_sendmsg+0x33a/0x4d0 net/bluetooth/l2cap_sock.c:1180
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2684
___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
__sys_sendmmsg+0x273/0x4d0 net/socket.c:2827
__do_sys_sendmmsg net/socket.c:2854 [inline]
__se_sys_sendmmsg net/socket.c:2851 [inline]
__x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2851
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed8cfcb649
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed8a791f58 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000000001f2 RCX: 00007fed8cfcb649
RDX: 000000000000000a RSI: 00007fed8a791f80 RDI: 0000000000000006
RBP: 00007fed8a791f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000040 R11: 0000000000000246 R12: 0000000000000006
R13: 0000000000000000 R14: 00007ffed10ed450 R15: 00007ffed10ed538
</TASK>
----------------
Code disassembly (best guess):
0: 49 81 c7 70 01 00 00 add $0x170,%r15
7: 4c 8d 35 86 dd 5b 0e lea 0xe5bdd86(%rip),%r14 # 0xe5bdd94
e: 48 89 f8 mov %rdi,%rax
11: 48 c1 e8 03 shr $0x3,%rax
15: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1)
19: 74 05 je 0x20
1b: e8 a4 20 a5 00 call 0xa520c4
20: 49 8b 75 18 mov 0x18(%r13),%rsi
24: 4c 89 f7 mov %r14,%rdi
27: 4c 89 fa mov %r15,%rdx
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 4c 89 e8 mov %r13,%rax
32: 48 c1 e8 03 shr $0x3,%rax
36: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1)
3a: 74 08 je 0x44
3c: 4c 89 ef mov %r13,%rdi
3f: e8 .byte 0xe8


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