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INFO: task hung in fuse_lookup

Status: upstream: reported syz repro on 2023/06/07 02:49
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+e762e7812fed7fbf7dad@syzkaller.appspotmail.com
First crash: 329d, last: 309d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2023/06/07 upstream (ToT) a4d7d7011219 C [report] INFO: task hung in fuse_lookup
▶ ▼ Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in fuse_lookup 4 1674d 1827d 0/1 auto-closed as invalid on 2020/01/29 21:30
linux-4.19 INFO: task hung in fuse_lookup reiserfs C error 12 445d 1722d 0/1 upstream: reported C repro on 2019/08/14 05:24
linux-4.14 INFO: task hung in fuse_lookup (3) 1 838d 838d 0/1 auto-closed as invalid on 2022/05/15 00:47
linux-6.1 INFO: task hung in fuse_lookup origin:upstream syz 3 30d 329d 0/3 upstream: reported syz repro on 2023/06/07 05:32
upstream INFO: task hung in fuse_lookup (3) fuse C done error 46 14h55m 1722d 0/26 upstream: reported C repro on 2019/08/14 09:48
linux-4.14 INFO: task hung in fuse_lookup (4) reiserfs C 2 450d 505d 0/1 upstream: reported C repro on 2022/12/13 09:09
linux-4.14 INFO: task hung in fuse_lookup (2) 1 1508d 1508d 0/1 auto-closed as invalid on 2020/07/13 23:30
upstream INFO: task hung in fuse_lookup fuse 16 2066d 2118d 0/26 closed as invalid on 2018/09/05 12:51
android-49 INFO: task hung in fuse_lookup C 112 1636d 1847d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in fuse_lookup (2) fuse C 13 1900d 2060d 0/26 closed as dup on 2018/09/10 08:43

Sample crash report:
INFO: task syz-executor.0:4036 blocked for more than 143 seconds.
      Not tainted 5.15.115-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:    0 pid: 4036 ppid:     1 flags:0x00000001
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0xf10/0x1e38 kernel/sched/core.c:6372
 schedule+0x11c/0x1c8 kernel/sched/core.c:6455
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6514
 __mutex_lock_common+0xba0/0x2154 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
 fuse_lock_inode+0xd4/0x11c fs/fuse/inode.c:436
 fuse_lookup+0xf0/0x4d4 fs/fuse/dir.c:423
 __lookup_slow+0x250/0x388 fs/namei.c:1659
 lookup_slow+0x60/0x84 fs/namei.c:1676
 walk_component+0x394/0x4cc fs/namei.c:1972
 link_path_walk+0x5a0/0xc38
 path_openat+0x1e8/0x26f0 fs/namei.c:3668
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
INFO: task syz-executor.0:4057 blocked for more than 143 seconds.
      Not tainted 5.15.115-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:    0 pid: 4057 ppid:  4036 flags:0x00000009
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0xf10/0x1e38 kernel/sched/core.c:6372
 schedule+0x11c/0x1c8 kernel/sched/core.c:6455
 request_wait_answer fs/fuse/dev.c:411 [inline]
 __fuse_request_send fs/fuse/dev.c:430 [inline]
 fuse_simple_request+0xea8/0x1758 fs/fuse/dev.c:515
 fuse_lookup_name+0x27c/0x6ac fs/fuse/dir.c:383
 fuse_lookup+0x13c/0x4d4 fs/fuse/dir.c:424
 __lookup_slow+0x250/0x388 fs/namei.c:1659
 lookup_slow+0x60/0x84 fs/namei.c:1676
 walk_component+0x394/0x4cc fs/namei.c:1972
 link_path_walk+0x5a0/0xc38
 path_openat+0x1e8/0x26f0 fs/namei.c:3668
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff800014aa19a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by getty/3730:
 #0: ffff0000d2df9098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001a2be2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
2 locks held by syz-executor.0/4036:
 #0: ffff0000df9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline]
 #0: ffff0000df9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow+0x50/0x84 fs/namei.c:1675
 #1: ffff0000df9d05b8 (&fi->mutex){+.+.}-{3:3}, at: fuse_lock_inode+0xd4/0x11c fs/fuse/inode.c:436
2 locks held by syz-executor.0/4057:
 #0: ffff0000df9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline]
 #0: ffff0000df9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow+0x50/0x84 fs/namei.c:1675
 #1: ffff0000df9d05b8 (&fi->mutex){+.+.}-{3:3}, at: fuse_lock_inode+0xd4/0x11c fs/fuse/inode.c:436

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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/07 02:48 linux-5.15.y d7af3e5ba454 a4ae4f42 .config console log report syz [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 INFO: task hung in fuse_lookup
2023/06/27 15:35 linux-5.15.y f67653019430 4cd5bb25 .config console log report syz [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in fuse_lookup
* Struck through repros no longer work on HEAD.