syzbot


INFO: task hung in flush_work
Status: upstream: reported C repro on 2019/04/21 07:04
Reported-by: syzbot+d920ef3da686d4330a35@syzkaller.appspotmail.com
First crash: 1126d, last: 720d

Fix bisection: the fix commit could be any of (bisect log):
  68d7a45eec10 Linux 4.14.113
  4139fb08c05f Linux 4.14.187
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in flush_work C error 306 1365d 1474d 0/22 upstream: reported C repro on 2018/05/07 15:47
android-49 INFO: task hung in flush_work C 28 1279d 1134d 0/3 public: reported C repro on 2019/04/13 00:00
android-414 INFO: task hung in flush_work 11 1140d 1134d 0/1 auto-closed as invalid on 2019/10/04 01:39

Sample crash report:
INFO: task syz-executor454:7556 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28848  7556   7105 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d1314db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc40 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffd4ac815bf R14: 00007f42d13159c0 R15: 0000000000000000
INFO: task syz-executor454:7614 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28848  7614   7106 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d12d2db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc68 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc60 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc6c
R13: 00007ffd4ac815bf R14: 00007f42d12d39c0 R15: 0000000000000000
INFO: task syz-executor454:7606 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28848  7606   7103 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d1314db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc40 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffd4ac815bf R14: 00007f42d13159c0 R15: 0000000000000000
INFO: task syz-executor454:7612 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28848  7612   7104 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d1314db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc40 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffd4ac815bf R14: 00007f42d13159c0 R15: 0000000000000000
INFO: task syz-executor454:7616 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28976  7616   7102 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d1314db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc40 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffd4ac815bf R14: 00007f42d13159c0 R15: 0000000000000000
INFO: task syz-executor454:7621 blocked for more than 140 seconds.
      Not tainted 4.14.113 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor454 D28848  7621   7101 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common kernel/sched/completion.c:123 [inline]
 wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
 flush_work+0x3eb/0x730 kernel/workqueue.c:2885
 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956
 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992
 p9_conn_destroy net/9p/trans_fd.c:872 [inline]
 p9_fd_close+0x2a1/0x450 net/9p/trans_fd.c:899
 p9_client_create+0x793/0x1130 net/9p/client.c:1095
 v9fs_session_init+0x1dc/0x1630 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4469a9
RSP: 002b:00007f42d1314db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 00000000004469a9
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000000000000
RBP: 00000000006dbc40 R08: 0000000020000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffd4ac815bf R14: 00007f42d13159c0 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by kworker/0:1/944:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089
1 lock held by khungtaskd/1008:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81486f98>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
2 locks held by kworker/1:2/2677:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089
2 locks held by kworker/0:2/3144:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089
1 lock held by rsyslogd/6949:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff81942cbb>] __fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/7072:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7073:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7074:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7075:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7076:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7077:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7078:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861b0323>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310c666>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by kworker/0:0/7201:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089
2 locks held by kworker/0:3/7202:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089
2 locks held by kworker/0:4/7381:
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] work_static include/linux/workqueue.h:199 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ("events"){+.+.}, at: [<ffffffff813d130e>] process_one_work+0x76e/0x1610 kernel/workqueue.c:2085
 #1:  ((&m->rq)){+.+.}, at: [<ffffffff813d134b>] process_one_work+0x7ab/0x1610 kernel/workqueue.c:2089

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

NMI backtrace for cpu 1
CPU: 1 PID: 1008 Comm: khungtaskd Not tainted 4.14.113 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x31c/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff861b0e02

Crashes (5):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/04/21 06:03 linux-4.14.y 68d7a45eec10 b0e8efcb .config log report syz C
ci2-linux-4-14 2019/08/01 01:21 linux-4.14.y 10d6aa565d05 c692b5bd .config log report
ci2-linux-4-14 2019/07/26 16:16 linux-4.14.y ff33472c282e 8fe30d3e .config log report
ci2-linux-4-14 2019/06/11 08:00 linux-4.14.y e6a95d8851f1 0159583c .config log report
ci2-linux-4-14 2019/04/23 18:19 linux-4.14.y 68d7a45eec10 2398edea .config log report