syzbot


INFO: task hung in fuse_lookup (2)

Status: auto-closed as invalid on 2020/07/13 23:30
Reported-by: syzbot+97ab7875344763abef12@syzkaller.appspotmail.com
First crash: 830d, last: 830d
similar bugs (7):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in fuse_lookup 4 997d 1149d 0/1 auto-closed as invalid on 2020/01/29 21:30
linux-4.19 INFO: task hung in fuse_lookup C error 6 5d09h 1045d 0/1 upstream: reported C repro on 2019/08/14 05:24
linux-4.14 INFO: task hung in fuse_lookup (3) 1 160d 160d 0/1 auto-closed as invalid on 2022/05/15 00:47
upstream INFO: task hung in fuse_lookup (3) C done error 19 148d 1045d 0/22 upstream: reported C repro on 2019/08/14 09:48
upstream INFO: task hung in fuse_lookup 16 1389d 1441d 0/22 closed as invalid on 2018/09/05 12:51
android-49 INFO: task hung in fuse_lookup C 112 959d 1170d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in fuse_lookup (2) C 13 1223d 1383d 0/22 closed as dup on 2018/09/10 08:43

Sample crash report:
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.3:7427 blocked for more than 140 seconds.
      Not tainted 4.14.173-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D25440  7427      1 0x00000004
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365
 fuse_lookup+0x6c/0x330 fs/fuse/dir.c:367
 lookup_slow+0x213/0x410 fs/namei.c:1696
 walk_component+0x648/0x1bc0 fs/namei.c:1825
 link_path_walk+0x717/0xed0 fs/namei.c:2154
 path_mountpoint+0xac/0x1970 fs/namei.c:2718
 filename_mountpoint+0x16c/0x320 fs/namei.c:2745
 SYSC_umount fs/namespace.c:1730 [inline]
 SyS_umount+0x10a/0x340 fs/namespace.c:1714
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45f277
RSP: 002b:00007fffd1f666d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 000000000002d752 RCX: 000000000045f277
RDX: 0000000000402f28 RSI: 0000000000000002 RDI: 00007fffd1f66780
RBP: 00000000000000cc R08: 0000000000000000 R09: 000000000000000f
R10: 000000000000000a R11: 0000000000000246 R12: 00007fffd1f67810
R13: 00000000020a1940 R14: 0000000000000000 R15: 00007fffd1f67810

Showing all locks held in the system:
1 lock held by khungtaskd/1057:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81465b23>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
2 locks held by getty/7383:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7384:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7385:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7386:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7387:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7388:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7389:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833ad812>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833a1454>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.3/7427:
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818d6129>] inode_lock_shared include/linux/fs.h:728 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818d6129>] lookup_slow+0x129/0x410 fs/namei.c:1674
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff82210f80>] fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365
2 locks held by syz-executor.3/9494:
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818d6129>] inode_lock_shared include/linux/fs.h:728 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818d6129>] lookup_slow+0x129/0x410 fs/namei.c:1674
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff82210f80>] fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365

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

NMI backtrace for cpu 1
CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 4.14.173-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+0x13e/0x194 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x139/0x17e 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+0x5e2/0xb80 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 121 Comm: kworker/u4:3 Not tainted 4.14.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff8880a9514300 task.stack: ffff8880a9518000
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/paravirt.h:784 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:797 [inline]
RIP: 0010:lock_acquire+0xac/0x3f0 kernel/locking/lockdep.c:3989
RSP: 0018:ffff8880a951fcb8 EFLAGS: 00000282
RAX: 0000000000000282 RBX: ffff8880a9514300 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880a9514b7c
RBP: ffffffff87d84360 R08: 0000000000000000 R09: 0000000000000000
R10: ffff8880a9514bd0 R11: ffff8880a9514300 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff79faee79 CR3: 0000000096228000 CR4: 00000000001406f0
DR0: 0000000020000100 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 rcu_lock_acquire include/linux/rcupdate.h:242 [inline]
 rcu_read_lock include/linux/rcupdate.h:629 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline]
 batadv_nc_worker+0x103/0x6d0 net/batman-adv/network-coding.c:726
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 00 0f 85 3d 03 00 00 48 83 3d f0 2f 8b 06 00 0f 84 95 02 00 00 9c 58 0f 1f 44 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 44 24 08 <48> c7 c0 90 66 d1 87 48 c1 e8 03 80 3c 10 00 0f 85 f3 02 00 00 

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/03/15 23:30 linux-4.14.y 12cd844a39ed 749688d2 .config log report