syzbot


INFO: task hung in __block_write_begin_int

Status: closed as invalid on 2018/03/27 11:14
Subsystems: fs
[Documentation on labels]
First crash: 2836d, last: 2836d

Sample crash report:
INFO: task syz-executor6:17529 blocked for more than 120 seconds.
      Not tainted 4.16.0-rc6+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D20976 17529   4240 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2862 [inline]
 __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440
 schedule+0xf5/0x430 kernel/sched/core.c:3499
 io_schedule+0x1c/0x70 kernel/sched/core.c:5115
 bit_wait_io+0x18/0x90 kernel/sched/wait_bit.c:259
 __wait_on_bit+0x88/0x130 kernel/sched/wait_bit.c:51
 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:109 [inline]
 __wait_on_buffer fs/buffer.c:118 [inline]
 wait_on_buffer include/linux/buffer_head.h:356 [inline]
 __block_write_begin_int+0x6fc/0x1610 fs/buffer.c:2019
 __block_write_begin fs/buffer.c:2031 [inline]
 block_write_begin+0xd2/0x2e0 fs/buffer.c:2090
 blkdev_write_begin+0x3c/0x50 fs/block_dev.c:584
 generic_perform_write+0x28f/0x600 mm/filemap.c:3138
 __generic_file_write_iter+0x366/0x5b0 mm/filemap.c:3263
 blkdev_write_iter+0x207/0x3e0 fs/block_dev.c:1908
 call_write_iter include/linux/fs.h:1782 [inline]
 do_iter_readv_writev+0x55c/0x830 fs/read_write.c:653
 do_iter_write+0x154/0x540 fs/read_write.c:932
 vfs_iter_write+0x77/0xb0 fs/read_write.c:945
 iter_file_splice_write+0x7db/0xf30 fs/splice.c:749
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x125/0x180 fs/splice.c:1018
 splice_direct_to_actor+0x2c1/0x820 fs/splice.c:973
 do_splice_direct+0x29b/0x3c0 fs/splice.c:1061
 do_sendfile+0x5c9/0xe80 fs/read_write.c:1413
 SYSC_sendfile64 fs/read_write.c:1468 [inline]
 SyS_sendfile64+0xbd/0x160 fs/read_write.c:1460
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x454879
RSP: 002b:00007faf77bb1c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007faf77bb26d4 RCX: 0000000000454879
RDX: 00000000200ddff8 RSI: 0000000000000014 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000102000001 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004bc R14: 00000000006f8240 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by khungtaskd/798:
 #0:  (rcu_read_lock){....}, at: [<0000000017dabd1f>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<0000000017dabd1f>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<00000000ad837dec>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470
1 lock held by rsyslogd/4068:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000120deaf5>] __fdget_pos+0x12b/0x190 fs/file.c:765
2 locks held by getty/4158:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4159:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4160:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4161:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4162:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4163:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4164:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000005c466b15>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000031db4be2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
5 locks held by kworker/1:4/5750:
 #0:  ((wq_completion)"cgroup_destroy"){+.+.}, at: [<0000000044df30b0>] work_static include/linux/workqueue.h:198 [inline]
 #0:  ((wq_completion)"cgroup_destroy"){+.+.}, at: [<0000000044df30b0>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ((wq_completion)"cgroup_destroy"){+.+.}, at: [<0000000044df30b0>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ((wq_completion)"cgroup_destroy"){+.+.}, at: [<0000000044df30b0>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084
 #1:  ((work_completion)(&css->destroy_work)){+.+.}, at: [<00000000fa42dbcc>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088
 #2:  (cgroup_mutex){+.+.}, at: [<00000000f73d5954>] css_killed_work_fn+0x93/0x5c0 kernel/cgroup/cgroup.c:4967
 #3:  (cpu_hotplug_lock.rw_sem){++++}, at: [<000000002e1a45cd>] get_online_cpus include/linux/cpu.h:124 [inline]
 #3:  (cpu_hotplug_lock.rw_sem){++++}, at: [<000000002e1a45cd>] memcg_deactivate_kmem_caches+0x21/0xf0 mm/slab_common.c:747
 #4:  (slab_mutex){+.+.}, at: [<00000000178eed3f>] memcg_deactivate_kmem_caches+0x2f/0xf0 mm/slab_common.c:750
4 locks held by kworker/0:8/7900:
 #0:  ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<0000000044df30b0>] work_static include/linux/workqueue.h:198 [inline]
 #0:  ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<0000000044df30b0>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<0000000044df30b0>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<0000000044df30b0>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084
 #1:  ((work_completion)(&cw->work)){+.+.}, at: [<00000000fa42dbcc>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088
 #2:  (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000c8ad0a6c>] get_online_cpus include/linux/cpu.h:124 [inline]
 #2:  (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000c8ad0a6c>] memcg_create_kmem_cache+0x16/0x170 mm/slab_common.c:619
 #3:  (slab_mutex){+.+.}, at: [<00000000401fc456>] memcg_create_kmem_cache+0x24/0x170 mm/slab_common.c:622
3 locks held by kworker/0:9/10529:
 #0:  ((wq_completion)"events"){+.+.}, at: [<0000000044df30b0>] work_static include/linux/workqueue.h:198 [inline]
 #0:  ((wq_completion)"events"){+.+.}, at: [<0000000044df30b0>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ((wq_completion)"events"){+.+.}, at: [<0000000044df30b0>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ((wq_completion)"events"){+.+.}, at: [<0000000044df30b0>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084
 #1:  (slab_caches_to_rcu_destroy_work){+.+.}, at: [<00000000fa42dbcc>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088
 #2:  (slab_mutex){+.+.}, at: [<00000000c25c009d>] slab_caches_to_rcu_destroy_workfn+0x25/0xc0 mm/slab_common.c:556

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

NMI backtrace for cpu 1
CPU: 1 PID: 798 Comm: khungtaskd Not tainted 4.16.0-rc6+ #1
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+0x194/0x24d lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x123/0x180 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:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1892 Comm: kworker/0:3 Not tainted 4.16.0-rc6+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: cgroup_destroy css_free_work_fn
RIP: 0010:qlist_move_cache+0x73/0xf0 mm/kasan/quarantine.c:275
RSP: 0018:ffff8801d1d87070 EFLAGS: 00000082
RAX: ffff8801b39ea040 RBX: 000077ff80000000 RCX: ffff8801b39ea040
RDX: ffff880198cd8980 RSI: ffff8801d1d87090 RDI: ffff8801db228f80
RBP: ffff8801d1d87080 R08: ffff8801ac7fe740 R09: 0000000080000000
R10: ffff8801ad90b680 R11: ffffea0000000000 R12: ffffea0006760f9f
R13: ffff880198cd8980 R14: ffffffff885ef2a0 R15: ffff880198cd8980
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 0000000006e22003 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 per_cpu_remove_cache+0x3f/0x60 mm/kasan/quarantine.c:294
 on_each_cpu+0xca/0x1b0 kernel/smp.c:604
 quarantine_remove_cache+0x55/0xf0 mm/kasan/quarantine.c:311
 kasan_cache_shutdown+0x9/0x10 mm/kasan/kasan.c:381
 shutdown_cache+0x15/0x1b0 mm/slab_common.c:577
 memcg_destroy_kmem_caches+0x62/0x80 mm/slab_common.c:781
 memcg_free_kmem mm/memcontrol.c:2856 [inline]
 mem_cgroup_css_free+0x2a4/0x3f0 mm/memcontrol.c:4298
 css_free_work_fn+0x1c8/0x1420 kernel/cgroup/cgroup.c:4541
 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Code: 3f 00 8b 40 14 74 7f 4c 8b 47 08 49 89 08 48 89 4f 08 48 c7 01 00 00 00 00 4c 89 d1 48 01 47 10 4d 85 d2 74 5c 48 89 c8 4c 8b 11 <4c> 01 c8 72 62 49 89 d8 4c 01 c0 48 c1 e8 0c 48 c1 e0 06 4c 01 

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/03/25 23:30 upstream bcfc1f455466 e033c1f1 .config console log report ci-upstream-kasan-gce-root
* Struck through repros no longer work on HEAD.