INFO: task hung in ath9k_hif_usb_firmware_cb

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 768a0741 usb: dwc2: gadget: Remove assigned but never used..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=111f235b100000
kernel config: https://syzkaller.appspot.com/x/.config?x=999be4eb2478ffa5
dashboard link: https://syzkaller.appspot.com/bug?extid=da8c2bed7fa646ad6fcf
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+da8c2b...@syzkaller.appspotmail.com

INFO: task kworker/0:0:5 blocked for more than 143 seconds.
Not tainted 5.8.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:0 D22168 5 2 0x80004000
Workqueue: events request_firmware_work_func
Call Trace:
context_switch kernel/sched/core.c:3453 [inline]
__schedule+0x88a/0x1cb0 kernel/sched/core.c:4178
schedule+0xcd/0x2b0 kernel/sched/core.c:4253
schedule_preempt_disabled+0xc/0x20 kernel/sched/core.c:4312
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10a0 kernel/locking/mutex.c:1103
device_lock include/linux/device.h:768 [inline]
ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1108 [inline]
ath9k_hif_usb_firmware_cb+0x3ac/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1241
request_firmware_work_func+0x126/0x250 drivers/base/firmware_loader/main.c:1001
process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x392/0x470 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Showing all locks held in the system:
3 locks held by kworker/0:0/5:
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240
#1: ffff8881da1d7da8 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244
#2: ffff8881d44bb218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#2: ffff8881d44bb218 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1108 [inline]
#2: ffff8881d44bb218 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_cb+0x3ac/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1241
1 lock held by khungtaskd/23:
#0: ffffffff873124a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5779
3 locks held by kworker/1:2/68:
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8881da028d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240
#1: ffff8881d5ae7da8 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244
#2: ffff8881d440b218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#2: ffff8881d440b218 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1108 [inline]
#2: ffff8881d440b218 (&dev->mutex){....}-{3:3}, at: ath9k_hif_usb_firmware_cb+0x3ac/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1241
1 lock held by in:imklog/213:
#0: ffff8881ca60a370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826
3 locks held by kworker/0:4/3049:
3 locks held by kworker/0:5/3055:
5 locks held by kworker/0:6/3096:
5 locks held by kworker/1:6/3310:
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240
#1: ffff8881d97f7da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244
#2: ffff8881d44bb218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#2: ffff8881d44bb218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x4390 drivers/usb/core/hub.c:5522
#3: ffff8881d9414218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#3: ffff8881d9414218 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850
#4: ffff8881c7a8f1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#4: ffff8881c7a8f1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850
3 locks held by kworker/1:8/4172:
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240
#1: ffff8881c746fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244
#2: ffff8881d440b218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline]
#2: ffff8881d440b218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x4390 drivers/usb/core/hub.c:5522
2 locks held by agetty/16081:
#0: ffff8881cba50098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
#1: ffffc900102882e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xf6/0x16e lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x74/0xb6 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1da/0x1f4 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
watchdog+0xd6a/0xfd0 kernel/hung_task.c:295
kthread+0x392/0x470 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 340 Comm: syz-executor.2 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0033:0x45cae4
Code: Bad RIP value.
RSP: 002b:00007ffd79517e20 EFLAGS: 00000217
RAX: 0000000000000000 RBX: 00000000000d7450 RCX: 000000000045b030
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffd79517e20
RBP: 00000000000002dd R08: 0000000000000001 R09: 0000000000e8b940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd79517e70 R14: 00000000000d7450 R15: 00007ffd79517e80
FS: 0000000000e8b940 GS: 0000000000000000


---
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[Tetsuo Handa]

This bug was reported on the same day with "INFO: task hung in ath6kl_usb_power_off" and
many of reports contain traces found in "INFO: task hung in ath6kl_usb_power_off".

Maybe the root cause is the same. Let's wait if "ath6kl: avoid flush_scheduled_work() usage" helps.

[Tetsuo Handa]

#syz dup: INFO: task hung in ath6kl_usb_power_off