syzbot


INFO: task hung in fuse_flush

Status: auto-closed as invalid on 2022/02/03 03:15
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 474d, last: 386d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in fuse_flush 1 618d 618d 0/1 auto-closed as invalid on 2021/07/16 16:14
linux-4.19 INFO: task hung in fuse_flush (2) 1 426d 426d 0/1 auto-closed as invalid on 2022/01/24 04:40
linux-4.14 INFO: task hung in fuse_flush C inconclusive 18 38d 303d 0/1 upstream: reported C repro on 2022/01/26 21:17
linux-4.19 INFO: task hung in fuse_flush (3) 81 12h55m 303d 0/1 upstream: reported on 2022/01/27 11:57

Sample crash report:
INFO: task syz-executor.1:2031 blocked for more than 143 seconds.
      Not tainted 5.15.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:28152 pid: 2031 ppid: 16565 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6250
 schedule+0xd2/0x260 kernel/sched/core.c:6323
 rwsem_down_write_slowpath+0x761/0x1130 kernel/locking/rwsem.c:1117
 __down_write_common kernel/locking/rwsem.c:1272 [inline]
 __down_write_common kernel/locking/rwsem.c:1269 [inline]
 __down_write kernel/locking/rwsem.c:1281 [inline]
 down_write+0x135/0x150 kernel/locking/rwsem.c:1528
 inode_lock include/linux/fs.h:783 [inline]
 fuse_flush+0x20b/0x5d0 fs/fuse/file.c:490
 filp_close+0xb4/0x170 fs/open.c:1310
 close_fd+0x6f/0xa0 fs/file.c:642
 __do_sys_close fs/open.c:1329 [inline]
 __se_sys_close fs/open.c:1327 [inline]
 __x64_sys_close+0x2f/0xa0 fs/open.c:1327
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcaf26fe72b
RSP: 002b:00007ffdf5736df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00007fcaf26fe72b
RDX: 0000001b2e02a71c RSI: ffffffff8939db02 RDI: 0000000000000006
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b2e02a100
R10: 0000000000000365 R11: 0000000000000293 R12: 00007fcaf285fb60
R13: 00007fcaf285fb60 R14: 00007fcaf285ef60 R15: 0000000000194f73
 </TASK>
INFO: task syz-executor.1:2069 blocked for more than 143 seconds.
      Not tainted 5.15.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:28120 pid: 2069 ppid: 16565 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6250
 schedule+0xd2/0x260 kernel/sched/core.c:6323
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x174/0x270 kernel/sched/completion.c:138
 fuse_direct_IO+0x716/0xf40 fs/fuse/file.c:2887
 generic_file_direct_write+0x1e8/0x540 mm/filemap.c:3670
 fuse_cache_write_iter fs/fuse/file.c:1325 [inline]
 fuse_file_write_iter+0x5c1/0xbb0 fs/fuse/file.c:1605
 call_write_iter include/linux/fs.h:2161 [inline]
 aio_write+0x350/0x7a0 fs/aio.c:1577
 __io_submit_one fs/aio.c:1832 [inline]
 io_submit_one+0xe09/0x1b80 fs/aio.c:1879
 __do_sys_io_submit fs/aio.c:1938 [inline]
 __se_sys_io_submit fs/aio.c:1908 [inline]
 __x64_sys_io_submit+0x18c/0x330 fs/aio.c:1908
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcaf274bae9
RSP: 002b:00007fcaefca0188 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fcaf285f020 RCX: 00007fcaf274bae9
RDX: 0000000020000780 RSI: 0000000000000004 RDI: 00007fcaf283a000
RBP: 00007fcaf27a5f25 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdf5736d8f R14: 00007fcaefca0300 R15: 0000000000022000
 </TASK>
INFO: task syz-executor.1:2111 blocked for more than 143 seconds.
      Not tainted 5.15.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:28768 pid: 2111 ppid:  2031 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6250
 schedule+0xd2/0x260 kernel/sched/core.c:6323
 rwsem_down_write_slowpath+0x761/0x1130 kernel/locking/rwsem.c:1117
 __down_write_common kernel/locking/rwsem.c:1272 [inline]
 __down_write_common kernel/locking/rwsem.c:1269 [inline]
 __down_write kernel/locking/rwsem.c:1281 [inline]
 down_write+0x135/0x150 kernel/locking/rwsem.c:1528
 inode_lock include/linux/fs.h:783 [inline]
 fuse_flush+0x20b/0x5d0 fs/fuse/file.c:490
 filp_close+0xb4/0x170 fs/open.c:1310
 close_files fs/file.c:403 [inline]
 put_files_struct fs/file.c:418 [inline]
 put_files_struct+0x1d0/0x350 fs/file.c:415
 exit_files+0x7e/0xa0 fs/file.c:435
 do_exit+0xbdd/0x2b40 kernel/exit.c:827
 do_group_exit+0x125/0x310 kernel/exit.c:929
 get_signal+0x47d/0x21d0 kernel/signal.c:2820
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcaf274bae9
RSP: 002b:00007fcaefc7f218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fcaf285f0e8 RCX: 00007fcaf274bae9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fcaf285f0e8
RBP: 00007fcaf285f0e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcaf285f0ec
R13: 00007ffdf5736d8f R14: 00007fcaefc7f300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8b983920 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
1 lock held by in:imklog/6175:
1 lock held by syz-executor.1/2031:
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: fuse_flush+0x20b/0x5d0 fs/fuse/file.c:490
1 lock held by syz-executor.1/2069:
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: fuse_cache_write_iter fs/fuse/file.c:1306 [inline]
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: fuse_file_write_iter+0x3c1/0xbb0 fs/fuse/file.c:1605
1 lock held by syz-executor.1/2111:
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
 #0: ffff88818a8c2310 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: fuse_flush+0x20b/0x5d0 fs/fuse/file.c:490

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8617 Comm: kworker/u4:8 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:debug_object_activate+0xa6/0x3e0 lib/debugobjects.c:656
Code: 48 c7 44 24 50 00 00 00 00 48 c7 44 24 40 00 00 00 00 48 c7 44 24 48 00 00 00 00 85 c0 c7 44 24 50 05 00 00 00 48 89 74 24 60 <75> 45 48 ba 00 00 00 00 00 fc ff df 49 01 d6 49 c7 06 00 00 00 00
RSP: 0018:ffffc900189f7960 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff8880b9c28280 RCX: 0000000000000000
RDX: ffff888080488000 RSI: ffffffff898df180 RDI: ffffc900189f7b88
RBP: ffffc900189f7b88 R08: 0000000000028280 R09: 0000000000000003
R10: ffffffff8166d297 R11: 0000000000000000 R12: ffff8880b9c282c8
R13: dffffc0000000000 R14: 1ffff9200313ef2e R15: 00000000ffffffff
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f987390e010 CR3: 000000000b68e000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 debug_timer_activate kernel/time/timer.c:729 [inline]
 __mod_timer+0x77d/0xe30 kernel/time/timer.c:1050
 schedule_timeout+0x145/0x2a0 kernel/time/timer.c:1880
 toggle_allocation_gate mm/kfence/core.c:633 [inline]
 toggle_allocation_gate+0x305/0x390 mm/kfence/core.c:618
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 c7 44 24 50 00 00 	movq   $0x0,0x50(%rsp)
   7:	00 00
   9:	48 c7 44 24 40 00 00 	movq   $0x0,0x40(%rsp)
  10:	00 00
  12:	48 c7 44 24 48 00 00 	movq   $0x0,0x48(%rsp)
  19:	00 00
  1b:	85 c0                	test   %eax,%eax
  1d:	c7 44 24 50 05 00 00 	movl   $0x5,0x50(%rsp)
  24:	00
  25:	48 89 74 24 60       	mov    %rsi,0x60(%rsp)
* 2a:	75 45                	jne    0x71 <-- trapping instruction
  2c:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  33:	fc ff df
  36:	49 01 d6             	add    %rdx,%r14
  39:	49 c7 06 00 00 00 00 	movq   $0x0,(%r14)

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2021/11/05 03:15 upstream 7ddb58cb0eca 4c1be0be .config log report info INFO: task hung in fuse_flush
ci-upstream-kasan-gce-root 2021/08/09 06:15 upstream 36a21d51725a 6972b106 .config log report info INFO: task hung in fuse_flush
* Struck through repros no longer work on HEAD.