syzbot


WARNING in hci_conn_drop (4)

Status: upstream: reported on 2026/05/15 12:05
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+195b4c12c5b8c9a8eb8b@syzkaller.appspotmail.com
First crash: 5d18h, last: 4d11h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] WARNING in hci_conn_drop (4) 0 (1) 2026/05/15 12:05
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in hci_conn_drop bluetooth -1 1 505d 501d 0/29 auto-obsoleted due to no activity on 2025/04/06 16:23
linux-5.15 WARNING in hci_conn_drop -1 3 585d 676d 0/3 auto-obsoleted due to no activity on 2025/01/16 13:59
upstream WARNING in hci_conn_drop (3) bluetooth -1 2 193d 225d 0/29 auto-obsoleted due to no activity on 2026/02/12 14:34
linux-6.1 WARNING in hci_conn_drop -1 1 690d 690d 0/3 auto-obsoleted due to no activity on 2024/10/03 23:48
upstream WARNING in hci_conn_drop (2) bluetooth -1 1 377d 373d 0/29 auto-obsoleted due to no activity on 2025/08/12 21:54

Sample crash report:
------------[ cut here ]------------
workqueue: cannot queue hci_conn_timeout on wq hci4
WARNING: kernel/workqueue.c:2298 at __queue_work+0xf6c/0x12f8 kernel/workqueue.c:2296, CPU#0: kworker/0:5/4769
Modules linked in:
CPU: 0 UID: 0 PID: 4769 Comm: kworker/0:5 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events l2cap_chan_timeout
pstate: 634000c5 (nZCv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __queue_work+0xf6c/0x12f8 kernel/workqueue.c:2296
lr : __queue_work+0xf6c/0x12f8 kernel/workqueue.c:2296
sp : ffff800092887810
x29: ffff800092887850 x28: ffff700012510f78 x27: ffff0000d64aba88
x26: ffff0000d629f800 x25: 0000000000000008 x24: ffff0000d629f9c0
x23: dfff800000000000 x22: ffff0000de09572c x21: 0000000004208060
x20: ffff800089f06000 x19: ffff0000c5968a58 x18: 1fffe00035c20e20
x17: ffff8000888db000 x16: ffff80008898cfc0 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000ff0100 x9 : 2aca8fde2d60a500
x8 : 2aca8fde2d60a500 x7 : ffff8000804886d0 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000000 x3 : ffff8000802f13b0
x2 : 0000000100000000 x1 : ffff0000de095700 x0 : 0000000000000000
Call trace:
 __queue_work+0xf6c/0x12f8 kernel/workqueue.c:2296 (P)
 __queue_delayed_work+0xf4/0x2b4 kernel/workqueue.c:2548
 queue_delayed_work_on+0xcc/0x140 kernel/workqueue.c:2600
 queue_delayed_work include/linux/workqueue.h:711 [inline]
 hci_conn_drop+0x174/0x29c include/net/bluetooth/hci_core.h:1712
 l2cap_chan_del+0x220/0x48c net/bluetooth/l2cap_core.c:672
 l2cap_chan_close+0x3e4/0x5ac net/bluetooth/l2cap_core.c:-1
 l2cap_chan_timeout+0x120/0x29c net/bluetooth/l2cap_core.c:431
 process_one_work+0x78c/0x173c kernel/workqueue.c:3302
 process_scheduled_works+0xdc/0x13c kernel/workqueue.c:3385
 worker_thread+0x770/0xbd0 kernel/workqueue.c:3466
 kthread+0x2f0/0x3c0 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:842
irq event stamp: 81246
hardirqs last  enabled at (81245): [<ffff800080351f60>] __cancel_work+0xf4/0x1a4 kernel/workqueue.c:4454
hardirqs last disabled at (81246): [<ffff80008034e144>] queue_delayed_work_on+0x54/0x140 kernel/workqueue.c:2596
softirqs last  enabled at (81238): [<ffff800084aa1108>] spin_unlock_bh include/linux/spinlock.h:396 [inline]
softirqs last  enabled at (81238): [<ffff800084aa1108>] release_sock+0x150/0x228 net/core/sock.c:3825
softirqs last disabled at (81234): [<ffff800084aa0fec>] spin_lock_bh include/linux/spinlock.h:348 [inline]
softirqs last disabled at (81234): [<ffff800084aa0fec>] release_sock+0x34/0x228 net/core/sock.c:3812
---[ end trace 0000000000000000 ]---

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/12 18:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5cbb61bf4168 d5b1a17d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in hci_conn_drop
2026/05/11 11:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5cbb61bf4168 e6eb7c0b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in hci_conn_drop
* Struck through repros no longer work on HEAD.