syzbot


INFO: task hung in fuse_lookup (3)

Status: auto-closed as invalid on 2022/05/15 00:47
Reported-by: syzbot+2758cd0b97cd34906a47@syzkaller.appspotmail.com
First crash: 163d, last: 163d
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 999d 1152d 0/1 auto-closed as invalid on 2020/01/29 21:30
linux-4.19 INFO: task hung in fuse_lookup C error 6 7d17h 1048d 0/1 upstream: reported C repro on 2019/08/14 05:24
upstream INFO: task hung in fuse_lookup (3) C done error 19 150d 1047d 0/22 upstream: reported C repro on 2019/08/14 09:48
linux-4.14 INFO: task hung in fuse_lookup (2) 1 833d 833d 0/1 auto-closed as invalid on 2020/07/13 23:30
upstream INFO: task hung in fuse_lookup 16 1392d 1443d 0/22 closed as invalid on 2018/09/05 12:51
android-49 INFO: task hung in fuse_lookup C 112 961d 1172d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in fuse_lookup (2) C 13 1226d 1385d 0/22 closed as dup on 2018/09/10 08:43

Sample crash report:
INFO: task syz-executor.2:7983 blocked for more than 140 seconds.
      Not tainted 4.14.262-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D24928  7983      1 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365
 fuse_lookup+0x74/0x390 fs/fuse/dir.c:367
 lookup_slow+0x20a/0x400 fs/namei.c:1696
 walk_component+0x6a1/0xbc0 fs/namei.c:1825
 link_path_walk+0x823/0x10a0 fs/namei.c:2154
 path_openat+0x15e/0x2970 fs/namei.c:3568
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f58ea40eb28
RSP: 002b:00007fff1c281cf0 EFLAGS: 00000287 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000708 RCX: 00007f58ea40eb28
RDX: 0000000000090800 RSI: 00007f58ea46828e RDI: 00000000ffffff9c
RBP: 00007fff1c281dbc R08: 0000000000090800 R09: 00007f58ea46828e
R10: 0000000000000000 R11: 0000000000000287 R12: 0000000000000000
R13: 000000000004ff1f R14: 000000000000000d R15: 00007fff1c281e20
INFO: task syz-executor.2:28506 blocked for more than 140 seconds.
      Not tainted 4.14.262-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D27680 28506   7983 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 request_wait_answer+0x30d/0x620 fs/fuse/dev.c:478
 __fuse_request_send+0x108/0x1a0 fs/fuse/dev.c:498
 fuse_request_send fs/fuse/dev.c:511 [inline]
 fuse_simple_request+0x2fa/0x790 fs/fuse/dev.c:569
 fuse_lookup_name+0x228/0x550 fs/fuse/dir.c:330
 fuse_lookup+0xcd/0x390 fs/fuse/dir.c:368
 lookup_slow+0x20a/0x400 fs/namei.c:1696
 walk_component+0x6a1/0xbc0 fs/namei.c:1825
 link_path_walk+0x823/0x10a0 fs/namei.c:2154
 path_openat+0x15e/0x2970 fs/namei.c:3568
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f58ea40efe9
RSP: 002b:00007f58e8d42168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f58ea522100 RCX: 00007f58ea40efe9
RDX: 0000000000000042 RSI: 0000000020002080 RDI: ffffffffffffff9c
RBP: 00007f58ea46908d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff1c281aff R14: 00007f58e8d42300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1534:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8701f0b7>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
2 locks held by syz-executor.2/7983:
 #0:  (&type->i_mutex_dir_key#8){++++}, at: [<ffffffff8188fb09>] inode_lock_shared include/linux/fs.h:729 [inline]
 #0:  (&type->i_mutex_dir_key#8){++++}, at: [<ffffffff8188fb09>] lookup_slow+0x129/0x400 fs/namei.c:1674
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff82302340>] fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365
2 locks held by syz-executor.2/28506:
 #0:  (&type->i_mutex_dir_key#8){++++}, at: [<ffffffff8188fb09>] inode_lock_shared include/linux/fs.h:729 [inline]
 #0:  (&type->i_mutex_dir_key#8){++++}, at: [<ffffffff8188fb09>] lookup_slow+0x129/0x400 fs/namei.c:1674
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff82302340>] fuse_lock_inode+0xb0/0xe0 fs/fuse/inode.c:365

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

NMI backtrace for cpu 1
CPU: 1 PID: 1534 Comm: khungtaskd Not tainted 4.14.262-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+0x1b2/0x281 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x180 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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8723efbe

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2022/01/15 00:46 linux-4.14.y 4ba8e26127c3 53e00b45 .config log report info INFO: task hung in fuse_lookup