Hello,
syzbot found the following issue on:
HEAD commit: 228da13e907e Linux 6.1.175
git tree: linux-6.1.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=17bb7b7a580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=4dd3c1715f0a309b
dashboard link:
https://syzkaller.appspot.com/bug?extid=2f6e82ffa2ed1d18cfd6
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/a1730af56ab4/disk-228da13e.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/eafe9b37a422/vmlinux-228da13e.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/7353ac7f337a/bzImage-228da13e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+2f6e82...@syzkaller.appspotmail.com
INFO: task kworker/0:0:7 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0 state:D stack:21304 pid:7 ppid:2 flags:0x00004000
Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
device_lock include/linux/device.h:885 [inline]
ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1163 [inline]
ath9k_hif_usb_firmware_cb+0x329/0x4b0 drivers/net/wireless/ath/ath9k/hif_usb.c:1296
request_firmware_work_func+0xfb/0x1b0 drivers/base/firmware_loader/main.c:1137
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Showing all locks held in the system:
3 locks held by kworker/0:0/7:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900000c7d00 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffff888027c56190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888027c56190 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1163 [inline]
#2: ffff888027c56190 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_cb+0x329/0x4b0 drivers/net/wireless/ath/ath9k/hif_usb.c:1296
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e7f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2f010 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by pvrusb2-context/2312:
#0: ffff888079e68188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_initialize+0xe1/0x3c10 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2326
#1: ffffffff8c9da930 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xf9/0x2b0 kernel/umh.c:218
1 lock held by syslogd/3622:
#0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
2 locks held by getty/4025:
#0: ffff888030245098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:3/4316:
#0: ffff8880b8f3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
#1: ffff8880b8f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
#2: ffff8880588ccee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#2: ffff8880588ccee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: ptr_ring_consume_bh include/linux/ptr_ring.h:365 [inline]
#2: ffff8880588ccee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: wg_packet_decrypt_worker+0x980/0xe00 drivers/net/wireguard/receive.c:499
6 locks held by kworker/1:6/4319:
#0: ffff8881436c7138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900041d7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffff888027c56190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888027c56190 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x5560 drivers/usb/core/hub.c:5845
#3: ffff88823bc2a990 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88823bc2a990 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x107/0x8a0 drivers/usb/core/hub.c:2305
#4: ffff88801d384118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#4: ffff88801d384118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1100 [inline]
#4: ffff88801d384118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb2/0x850 drivers/base/dd.c:1303
#5: ffff888079e68188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_disconnect+0x69/0x500 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2710
4 locks held by udevd/4418:
#0: ffff888018e738b8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
#1: ffff88805541e488 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x58/0x410 fs/kernfs/file.c:172
#2: ffff888027c011d8 (kn->active#33){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027c011d8 (kn->active#33){++++}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff88823bc2a990 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:890 [inline]
#3: ffff88823bc2a990 (&dev->mutex){....}-{3:3}, at: serial_show+0x22/0x90 drivers/usb/core/sysfs.c:142
7 locks held by kworker/0:7/4933:
1 lock held by syz.5.608/7259:
#0: ffffffff8cb33a00 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:228 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:240 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4748 [inline]
RIP: 0010:__lock_acquire+0x93a/0x7d10 kernel/locking/lockdep.c:4999
Code: 01 00 00 41 8b 04 24 41 89 c6 41 81 e6 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 40 f2 af 90 be 08 00 00 00 e8 f6 35 6f 00 <4c> 0f a3 35 4e a3 4b 0f 73 1a 4b 8d 04 76 c1 e0 06 4c 8d b0 00 71
RSP: 0018:ffffc90000107840 EFLAGS: 00000056
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81644eea
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90aff318
RBP: ffffc90000107a90 R08: ffffffff90aff31f R09: 1ffffffff215fe63
R10: dffffc0000000000 R11: fffffbfff215fe64 R12: ffff88813fec4728
R13: ffff88813fec4704 R14: 00000000000006c9 R15: ffff88813fec4728
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f95d63ea2f8 CR3: 000000007e221000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock include/linux/rcupdate.h:791 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0xeb/0x600 net/batman-adv/network-coding.c:719
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
---
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