syzbot


WARNING in l2cap_chan_send

Status: upstream: reported on 2026/02/05 13:43
Reported-by: syzbot+307f5261162016128e88@syzkaller.appspotmail.com
First crash: 107d, last: 9d05h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING in l2cap_chan_send (2) -1 1 153d 153d 0/3 auto-obsoleted due to no activity on 2026/03/31 03:01
upstream WARNING in l2cap_chan_send prio:high bluetooth -1 57 39d 770d 0/29 upstream: reported on 2024/04/14 00:26
linux-6.1 WARNING in l2cap_chan_send -1 1 421d 421d 0/3 auto-obsoleted due to no activity on 2025/07/06 18:42

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 9758 at kernel/workqueue.c:1453 __queue_work+0xc04/0xd50 kernel/workqueue.c:1453
Modules linked in:
CPU: 1 PID: 9758 Comm: syz.3.1193 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__queue_work+0xc04/0xd50 kernel/workqueue.c:1453
Code: fc ff ff 48 8b 4c 24 08 80 e1 07 80 c1 03 38 c1 0f 8c 13 fd ff ff 48 8b 7c 24 08 e8 b6 48 70 00 e9 04 fd ff ff e8 ec 29 2b 00 <0f> 0b 48 83 c4 50 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 d6 29 2b 00
RSP: 0018:ffffc900031cf6d8 EFLAGS: 00010083
RAX: ffffffff814e0aa4 RBX: 0000000000010000 RCX: 0000000000080000
RDX: ffffc90003c72000 RSI: 0000000000002a18 RDI: 0000000000002a19
RBP: 0000000000000000 R08: ffff888062468b7f R09: 1ffff1100c48d16f
R10: dffffc0000000000 R11: ffffed100c48d170 R12: 0000000000000200
R13: ffff88807a6849c0 R14: ffff88807a684800 R15: 0000000000000008
FS:  00007f5af98f06c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000080 CR3: 00000000683e3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 queue_work_on+0x124/0x1f0 kernel/workqueue.c:1559
 l2cap_chan_send+0x3ca/0x25e0 net/bluetooth/l2cap_core.c:-1
 l2cap_sock_sendmsg+0x1aa/0x2b0 net/bluetooth/l2cap_sock.c:1173
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1089
 do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x281/0x480 fs/read_write.c:971
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5afb696e59
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:00007f5af98f0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f5afb90ffa0 RCX: 00007f5afb696e59
RDX: 0000000000000001 RSI: 00002000000008c0 RDI: 0000000000000005
RBP: 00007f5afb72cd6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5afb910038 R14: 00007f5afb90ffa0 R15: 00007ffec71da4d8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/14 20:21 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in l2cap_chan_send
2026/02/05 13:42 linux-5.15.y 9eec9a14ee10 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in l2cap_chan_send
* Struck through repros no longer work on HEAD.