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INFO: task hung in flush_work

Status: public: reported C repro on 2019/04/13 00:00
Reported-by: syzbot+3eec13fbbe882dc936b5@syzkaller.appspotmail.com
First crash: 2327d, last: 2195d
▶ ▼ Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in flush_work v9fs C error 306 2281d 2390d 0/28 auto-obsoleted due to no activity on 2023/04/12 14:31
linux-4.14 INFO: task hung in flush_work C inconclusive 5 1635d 2041d 0/1 upstream: reported C repro on 2019/04/21 07:04
android-414 INFO: task hung in flush_work 11 2055d 2049d 0/1 auto-closed as invalid on 2019/10/04 01:39

Sample crash report:
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
INFO: task syz-executor280:2348 blocked for more than 140 seconds.
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
      Not tainted 4.9.124+ #85
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor280 D
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
29384  2348   2347 0x00000004
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 ffff8801bb47df00 ffff8801bb514d00 ffff8801bb514200 ffff8801bb6f97c0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 ffff8801db7210d8 ffff8801bb6f78d0 ffffffff8277cf52 ffff8801bb47e7c8
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 ffffffff83a916a0 ffff8801bb47e7d0 00000000000039ab ffff8801db7219b0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
Call Trace:
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8277e47f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff82788aa5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1768
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8277fea9>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff8277fea9>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff8277fea9>] wait_for_common+0x2f9/0x400 kernel/sched/completion.c:101
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8277ffc8>] wait_for_completion+0x18/0x20 kernel/sched/completion.c:122
 [<ffffffff8112bc34>] flush_work+0x3a4/0x6c0 kernel/workqueue.c:2846
 [<ffffffff8112f19e>] __cancel_work_timer+0x17e/0x440 kernel/workqueue.c:2912
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8112f477>] cancel_work_sync+0x17/0x20 kernel/workqueue.c:2947
 [<ffffffff820b1a80>] uhid_dev_destroy+0x70/0xf0 drivers/hid/uhid.c:578
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff820b1b51>] uhid_char_release+0x51/0xb0 drivers/hid/uhid.c:655
 [<ffffffff815030b3>] __fput+0x263/0x700 fs/file_table.c:208
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff815035d5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8113c37c>] task_work_run+0x10c/0x180 kernel/task_work.c:116
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff81003e49>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff81003e49>] exit_to_usermode_loop+0x129/0x150 arch/x86/entry/common.c:161
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8100570d>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff8100570d>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff8100570d>] do_syscall_64+0x35d/0x480 arch/x86/entry/common.c:287
 [<ffffffff8278c053>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0

Showing all locks held in the system:
2 locks held by khungtaskd/24:
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131401c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131401c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 #1:  (tasklist_lock
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
){.+.+..}, at: [<ffffffff813f99b9>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
1 lock held by rsyslogd/2113:
 #0:  (&f->f_pos_lock
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
){+.+.+.}, at: [<ffffffff8155eadc>] __fdget_pos+0xac/0xd0 fs/file.c:781
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
2 locks held by getty/2209:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278a122>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81cde522>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.124+ #85
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 ffff8801d9497d08 ffffffff81af4b39 0000000000000000 0000000000000001
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 0000000000000001 0000000000000001 ffffffff81096740 ffff8801d9497d40
 ffffffff81aff897
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 0000000000000001 0000000000000000 0000000000000003
 [<ffffffff81af4b39>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af4b39>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff81aff897>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff81aff82a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff81096844>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff813145ad>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff813145ad>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813145ad>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813145ad>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff811410dd>] kthread+0x26d/0x300 kernel/kthread.c:211
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
 [<ffffffff8278c21c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
Sending NMI from CPU 1 to CPUs 0:
hid-generic 0000:0000:0000.0348: unknown main item tag 0x0
NMI backtrace for cpu 0
CPU: 0 PID: 351 Comm: kworker/0:2 Not tainted 4.9.124+ #85
Workqueue: events uhid_device_add_workerc
task: ffff8801d568af80 task.stack: ffff8801d3eb0000
RIP: 0010:[<ffffffff81165062>] c [<ffffffff81165062>] get_lock_parent_ip include/linux/ftrace.h:731 [inline]
RIP: 0010:[<ffffffff81165062>] c [<ffffffff81165062>] preempt_latency_start kernel/sched/core.c:3224 [inline]
RIP: 0010:[<ffffffff81165062>] c [<ffffffff81165062>] preempt_count_add+0xc2/0x170 kernel/sched/core.c:3249
RSP: 0018:ffff8801d3eb7238  EFLAGS: 00000002
RAX: ffff8801d3eb7270 RBX: ffffffff811f7f13 RCX: 1ffff1003aad170f
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8278b58e
RBP: ffff8801d3eb7248 R08: ffff8801d568b878 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000292
R13: 000000000000003a R14: 0000000000000006 R15: ffffffff83fc75e0
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff93c201f4 CR3: 00000001c9b7c000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff82ec5120c 0000000000000292c ffff8801d3eb7270c ffffffff8278b58ec
 ffff8801d568b828c 0000000000000000c ffffffff82ec5120c ffff8801d3eb7298c
 ffffffff811f7f13c 0000000000000006c 0000000000000000c ffffffff81221ac3c
Call Trace:
 [<ffffffff8278b58e>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 [<ffffffff8278b58e>] _raw_spin_lock_irqsave+0x2e/0x70 kernel/locking/spinlock.c:159
 [<ffffffff811f7f13>] down_trylock+0x13/0x70 kernel/locking/semaphore.c:135
 [<ffffffff8121e5e2>] __down_trylock_console_sem kernel/printk/printk.c:220 [inline]
 [<ffffffff8121e5e2>] console_trylock+0x22/0x150 kernel/printk/printk.c:2230
 [<ffffffff81221ac3>] vprintk_emit+0x2b3/0x790 kernel/printk/printk.c:1902
 [<ffffffff81d42d31>] dev_vprintk_emit+0x211/0x650 drivers/base/core.c:2204
 [<ffffffff81d4321e>] dev_printk_emit+0xae/0xe0 drivers/base/core.c:2215
 [<ffffffff81d434d3>] __dev_printk+0x103/0x270 drivers/base/core.c:2227
 [<ffffffff81d43b58>] dev_err+0xd8/0x110 drivers/base/core.c:2270
 [<ffffffff820941cd>] hid_parser_main+0x59d/0x980 drivers/hid/hid-core.c:555
 [<ffffffff820914fe>] hid_open_report+0x38e/0x6f0 drivers/hid/hid-core.c:1010
 [<ffffffff8209598d>] hid_device_probe+0x25d/0x4e0 drivers/hid/hid-core.c:2234
 [<ffffffff81d4e187>] really_probe drivers/base/dd.c:367 [inline]
 [<ffffffff81d4e187>] driver_probe_device+0x217/0x660 drivers/base/dd.c:507
 [<ffffffff81d4e9a5>] __device_attach_driver+0x205/0x270 drivers/base/dd.c:602
 [<ffffffff81d48632>] bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:463
 [<ffffffff81d4dd81>] __device_attach+0x211/0x300 drivers/base/dd.c:659
 [<ffffffff81d4eaaa>] device_initial_probe+0x1a/0x20 drivers/base/dd.c:706
 [<ffffffff81d4bb49>] bus_probe_device+0x1e9/0x290 drivers/base/bus.c:557
 [<ffffffff81d45381>] device_add+0x861/0x1520 drivers/base/core.c:1140
 [<ffffffff8209982a>] hid_add_device+0x31a/0x940 drivers/hid/hid-core.c:2710
 [<ffffffff820b1bf8>] uhid_device_add_worker+0x48/0x160 drivers/hid/uhid.c:66
 [<ffffffff8112fcf1>] process_one_work+0x791/0x1470 kernel/workqueue.c:2092
 [<ffffffff81130aa6>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff811410dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278c21c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: c00 c00 cfc cff cdf c48 c89 cfa c48 cc1 cea c03 c80 c3c c02 c00 c0f c85 ca4 c00 c00 c00 c49 c89 c9c c24 cb0 c11 c00 c00 c5b c41 c5c c5d cc3 c48 c8b c45 c00 c48 c8b c58 c08 c<48> c89 cdf ce8 c76 c5f c0a c00 c85 cc0 c74 cb3 c48 c8b c45 c00 c48 c8b c00 c48 c8b c

Crashes (28):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/09/03 05:56 https://android.googlesource.com/kernel/common android-4.9 a06ea261bc2a a4718693 .config console log report syz C ci-android-49-kasan-gce
2018/07/09 15:01 https://android.googlesource.com/kernel/common android-4.9 03c70feafdb2 f25e5770 .config console log report syz C ci-android-49-kasan-gce-root
2018/11/18 10:28 https://android.googlesource.com/kernel/common android-4.9 109a48ed2f69 adf636a8 .config console log report syz C ci-android-49-kasan-gce-386
2018/10/30 11:49 https://android.googlesource.com/kernel/common android-4.9 4ba3f69128be 2f1090da .config console log report ci-android-49-kasan-gce-root
2018/08/28 03:17 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 7ef1de9e .config console log report ci-android-49-kasan-gce-root
2018/08/26 14:56 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 758cd203 .config console log report ci-android-49-kasan-gce-root
2018/08/23 03:50 https://android.googlesource.com/kernel/common android-4.9 8dd3fc2ed765 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/18 09:38 https://android.googlesource.com/kernel/common android-4.9 681e57bb080a db1858f6 .config console log report ci-android-49-kasan-gce-root
2018/08/17 17:15 https://android.googlesource.com/kernel/common android-4.9 f85543ba3c54 738da825 .config console log report ci-android-49-kasan-gce-root
2018/08/15 09:23 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 0e6dcb88 .config console log report ci-android-49-kasan-gce-root
2018/08/15 08:00 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 0e6dcb88 .config console log report ci-android-49-kasan-gce-root
2018/08/14 05:37 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/11 22:02 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/10 18:43 https://android.googlesource.com/kernel/common android-4.9 92e87041ed2d 1fb62d58 .config console log report ci-android-49-kasan-gce-root
2018/08/09 22:05 https://android.googlesource.com/kernel/common android-4.9 92e87041ed2d 1fb62d58 .config console log report ci-android-49-kasan-gce-root
2018/08/09 09:56 https://android.googlesource.com/kernel/common android-4.9 856452b4f22e 2eeda842 .config console log report ci-android-49-kasan-gce-root
2018/08/03 03:24 https://android.googlesource.com/kernel/common android-4.9 0137ea2134c0 5b7e23bb .config console log report ci-android-49-kasan-gce-root
2018/08/02 18:16 https://android.googlesource.com/kernel/common android-4.9 0137ea2134c0 0a7cf4ec .config console log report ci-android-49-kasan-gce-root
2018/08/02 13:21 https://android.googlesource.com/kernel/common android-4.9 0137ea2134c0 0a7cf4ec .config console log report ci-android-49-kasan-gce-root
2018/07/31 22:07 https://android.googlesource.com/kernel/common android-4.9 90e7a9002952 1477993e .config console log report ci-android-49-kasan-gce-root
2018/07/30 18:56 https://android.googlesource.com/kernel/common android-4.9 990559158c7b 1a381291 .config console log report ci-android-49-kasan-gce-root
2018/07/29 15:59 https://android.googlesource.com/kernel/common android-4.9 990559158c7b 0824d7a1 .config console log report ci-android-49-kasan-gce-root
2018/07/22 23:57 https://android.googlesource.com/kernel/common android-4.9 47bbcd6bf8f9 8cc079c3 .config console log report ci-android-49-kasan-gce-root
2018/07/22 21:31 https://android.googlesource.com/kernel/common android-4.9 47bbcd6bf8f9 8cc079c3 .config console log report ci-android-49-kasan-gce-root
2018/07/20 07:12 https://android.googlesource.com/kernel/common android-4.9 47bbcd6bf8f9 49f35839 .config console log report ci-android-49-kasan-gce-root
2018/07/12 05:17 https://android.googlesource.com/kernel/common android-4.9 9e7903954483 2e0e3130 .config console log report ci-android-49-kasan-gce
2018/07/11 16:40 https://android.googlesource.com/kernel/common android-4.9 9e7903954483 2e0e3130 .config console log report ci-android-49-kasan-gce
2018/07/11 11:14 https://android.googlesource.com/kernel/common android-4.9 03c70feafdb2 2e0e3130 .config console log report ci-android-49-kasan-gce
* Struck through repros no longer work on HEAD.