syzbot


INFO: task hung in sync_inodes_sb (2)

Status: upstream: reported C repro on 2021/01/07 19:48
Reported-by: syzbot+d72364f87ba3a6d6eec1@syzkaller.appspotmail.com
First crash: 585d, last: 29d
similar bugs (8):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in sync_inodes_sb (2) 4 1211d 1229d 0/23 auto-closed as invalid on 2019/10/19 16:22
upstream INFO: task hung in sync_inodes_sb (3) C done 6 955d 963d 16/23 fixed on 2020/02/14 01:19
upstream INFO: task hung in sync_inodes_sb 58 1309d 1547d 0/23 closed as dup on 2018/09/08 15:37
linux-4.14 INFO: task hung in sync_inodes_sb 1 924d 924d 0/1 auto-closed as invalid on 2020/06/02 17:26
android-49 INFO: task hung in sync_inodes_sb 11 1449d 1528d 0/3 auto-closed as invalid on 2019/02/24 06:19
android-49 INFO: task hung in sync_inodes_sb (2) 2 1038d 1200d 0/3 auto-closed as invalid on 2020/02/10 00:14
upstream INFO: task hung in sync_inodes_sb (4) C done inconclusive 6 125d 633d 0/23 upstream: reported C repro on 2020/11/21 04:55
linux-4.19 INFO: task hung in sync_inodes_sb C error 4 253d 676d 0/1 upstream: reported C repro on 2020/10/09 07:19

Sample crash report:
NILFS (loop0): mounting unchecked fs
NILFS (loop0): recovery complete
NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
NILFS (loop0): unrecognized mount option "mode=00000000000000000007777"
INFO: task syz-executor694:8019 blocked for more than 140 seconds.
      Not tainted 4.14.213-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D29712  8019   8009 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 wb_wait_for_completion fs/fs-writeback.c:222 [inline]
 wb_wait_for_completion+0x118/0x170 fs/fs-writeback.c:218
 sync_inodes_sb+0x173/0x880 fs/fs-writeback.c:2471
 __sync_filesystem fs/sync.c:34 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x12f/0x230 fs/sync.c:48
 nilfs_remount+0x51/0x470 fs/nilfs2/super.c:1129
 do_remount_sb+0x150/0x530 fs/super.c:868
 do_remount fs/namespace.c:2370 [inline]
 do_mount+0x1632/0x2a00 fs/namespace.c:2870
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x44b5e9
RSP: 002b:00007f9b3a9d1d88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006ddc38 RCX: 000000000044b5e9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000000
RBP: 00000000006ddc30 R08: 0000000020000440 R09: 0000000000000000
R10: 0000000000000020 R11: 0000000000000246 R12: 000000005f671b56
R13: 000000005f671b56 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by kworker/u4:1/22:
 #0:  ("writeback"){+.+.}, at: [<ffffffff81373630>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087
 #1:  ((&(&wb->dwork)->work)){+.+.}, at: [<ffffffff81373666>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091
1 lock held by khungtaskd/1530:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81430dd4>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
2 locks held by syz-executor694/8019:
 #0:  (&type->s_umount_key#47){+.+.}, at: [<ffffffff819092e7>] do_remount fs/namespace.c:2364 [inline]
 #0:  (&type->s_umount_key#47){+.+.}, at: [<ffffffff819092e7>] do_mount+0x837/0x2a00 fs/namespace.c:2870
 #1:  (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff8192dfa6>] bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline]
 #1:  (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff8192dfa6>] sync_inodes_sb+0x156/0x880 fs/fs-writeback.c:2469

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

NMI backtrace for cpu 0
CPU: 0 PID: 1530 Comm: khungtaskd Not tainted 4.14.213-syzkaller #0
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+0x1b2/0x283 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5b9/0xb40 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8 Comm: rcu_preempt Not tainted 4.14.213-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880b5414200 task.stack: ffff8880b5418000
RIP: 0010:lock_release+0x27/0x870 kernel/locking/lockdep.c:4007
RSP: 0018:ffff8880b541fa60 EFLAGS: 00000086
RAX: dffffc0000000000 RBX: 0000000000000086 RCX: ffffffff88f7fd40
RDX: ffffffff8321e8aa RSI: 0000000000000001 RDI: ffffffff8bfb09e0
RBP: ffffffff8bfb09e0 R08: ffffffff8b9ac430 R09: 0000000000000086
R10: ffff8880b5414ab0 R11: ffff8880b5414200 R12: ffffffff8321e8aa
R13: 1ffff11016a83f64 R14: ffff8880b541fd18 R15: ffffffff8bfb09c8
FS:  0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6e1df7d000 CR3: 00000000a1849000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_unlock_irqrestore+0x1b/0xe0 kernel/locking/spinlock.c:192
 debug_object_deactivate lib/debugobjects.c:530 [inline]
 debug_object_deactivate+0x1da/0x2e0 lib/debugobjects.c:491
 debug_timer_deactivate kernel/time/timer.c:698 [inline]
 debug_deactivate kernel/time/timer.c:750 [inline]
 detach_timer kernel/time/timer.c:790 [inline]
 detach_if_pending+0x82/0x430 kernel/time/timer.c:809
 try_to_del_timer_sync+0x9a/0xe0 kernel/time/timer.c:1181
 del_timer_sync+0x17c/0x240 kernel/time/timer.c:1246
 schedule_timeout+0x4b7/0xe90 kernel/time/timer.c:1748
 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 0f 1f 40 00 48 b8 00 00 00 00 00 fc ff df 41 57 41 56 41 55 41 54 49 89 d4 55 48 89 fd 53 48 83 ec 58 48 c7 44 24 18 b3 8a b5 41 <48> 8d 5c 24 18 48 c7 44 24 20 74 5c b5 88 48 c1 eb 03 48 c7 44 

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2022/07/17 21:46 linux-4.14.y 424a46ea058e c104d4a3 .config log report syz C
ci2-linux-4-14 2022/06/17 21:19 linux-4.14.y 84bae26850e3 c104d4a3 .config log report syz C
ci2-linux-4-14 2022/05/18 19:33 linux-4.14.y dffb5c6ff09c c104d4a3 .config log report syz C
ci2-linux-4-14 2022/04/18 18:38 linux-4.14.y 74766a973637 c104d4a3 .config log report syz C
ci2-linux-4-14 2022/03/19 17:56 linux-4.14.y eb045674aab3 c104d4a3 .config log report syz C
ci2-linux-4-14 2022/02/17 17:24 linux-4.14.y a35d65bedfbc c104d4a3 .config log report syz C
ci2-linux-4-14 2022/01/18 16:56 linux-4.14.y 4ba8e26127c3 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/12/19 16:27 linux-4.14.y 9dfbac0e6b86 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/11/19 15:56 linux-4.14.y 5f9f3b0057d5 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/10/20 14:19 linux-4.14.y 2760370b1649 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/09/20 13:54 linux-4.14.y f96eb53cbd76 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/08/21 13:28 linux-4.14.y 162b95d01320 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/07/22 13:02 linux-4.14.y 964f3712e6a7 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/06/22 10:31 linux-4.14.y cfb41ef9deb1 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/05/22 18:17 linux-4.14.y 96afcb20f36f c104d4a3 .config log report syz C
ci2-linux-4-14 2021/03/24 05:03 linux-4.14.y cb83ddcd5332 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/02/22 04:31 linux-4.14.y 29c52025152b c104d4a3 .config log report syz C
Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2021/01/08 05:17 linux-4.14.y 1752938529c6 c104d4a3 .config log report syz C
ci2-linux-4-14 2021/04/22 17:08 linux-4.14.y cf256fbcbe34 33c28d03 .config log report info INFO: task hung in sync_inodes_sb
ci2-linux-4-14 2021/04/09 12:45 linux-4.14.y 0cc244011f40 6a81331a .config log report info INFO: task hung in sync_inodes_sb
ci2-linux-4-14 2021/01/12 13:13 linux-4.14.y ec822b3e8bf4 2c1f2513 .config log report info
ci2-linux-4-14 2021/01/08 02:53 linux-4.14.y 1752938529c6 c104d4a3 .config log report info
ci2-linux-4-14 2021/01/07 19:47 linux-4.14.y 1752938529c6 c104d4a3 .config log report info