syzbot


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: 494d, last: 11d
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 1838d 1991d 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 610d 1887d 0/1 upstream: reported C repro on 2019/08/14 05:24
linux-4.14 INFO: task hung in fuse_lookup (3) 1 1002d 1002d 0/1 auto-closed as invalid on 2022/05/15 00:47
linux-6.1 INFO: task hung in fuse_lookup origin:upstream syz error 3 195d 494d 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 10d 1887d 0/28 upstream: reported C repro on 2019/08/14 09:48
linux-4.14 INFO: task hung in fuse_lookup (4) reiserfs C 2 615d 670d 0/1 upstream: reported C repro on 2022/12/13 09:09
linux-4.14 INFO: task hung in fuse_lookup (2) 1 1672d 1672d 0/1 auto-closed as invalid on 2020/07/13 23:30
upstream INFO: task hung in fuse_lookup fuse 16 2231d 2283d 0/28 closed as invalid on 2018/09/05 12:51
android-49 INFO: task hung in fuse_lookup C 112 1801d 2012d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in fuse_lookup (2) fuse C 13 2065d 2225d 0/28 closed as dup on 2018/09/10 08:43
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/10/01 21:31 16m retest repro linux-5.15.y report log
2024/10/01 21:31 15m retest repro linux-5.15.y report log

Sample crash report:
INFO: task syz-executor.0:3571 blocked for more than 143 seconds.
      Not tainted 5.15.118-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:18848 pid: 3571 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0x12c4/0x4590 kernel/sched/core.c:6372
 schedule+0x11b/0x1f0 kernel/sched/core.c:6455
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6514
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 fuse_lock_inode+0xcf/0x120 fs/fuse/inode.c:436
 fuse_lookup+0x111/0x600 fs/fuse/dir.c:423
 __lookup_slow+0x275/0x3d0 fs/namei.c:1659
 lookup_slow+0x53/0x70 fs/namei.c:1676
 walk_component+0x48c/0x610 fs/namei.c:1972
 link_path_walk+0x642/0xd90
 path_openat+0x249/0x2f20 fs/namei.c:3668
 do_filp_open+0x21c/0x460 fs/namei.c:3699
 do_sys_openat2+0x13b/0x500 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]
 __x64_sys_openat+0x243/0x290 fs/open.c:1238
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fd2336fee98
RSP: 002b:00007ffe1f788ed0 EFLAGS: 00000287 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd2336fee98
RDX: 0000000000090800 RSI: 00007fd2337494df RDI: 00000000ffffff9c
RBP: 00007ffe1f788f9c R08: 0000000000090800 R09: 00007fd2337494df
R10: 0000000000000000 R11: 0000000000000287 R12: 0000000000000000
R13: 0000000000108cac R14: 0000000000000006 R15: 00007ffe1f789000
 </TASK>
INFO: task syz-executor.0:3591 blocked for more than 143 seconds.
      Not tainted 5.15.118-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:24464 pid: 3591 ppid:  3571 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0x12c4/0x4590 kernel/sched/core.c:6372
 schedule+0x11b/0x1f0 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+0x112f/0x1a00 fs/fuse/dev.c:515
 fuse_lookup_name+0x354/0x820 fs/fuse/dir.c:383
 fuse_lookup+0x17e/0x600 fs/fuse/dir.c:424
 __lookup_slow+0x275/0x3d0 fs/namei.c:1659
 lookup_slow+0x53/0x70 fs/namei.c:1676
 walk_component+0x48c/0x610 fs/namei.c:1972
 link_path_walk+0x642/0xd90
 path_openat+0x249/0x2f20 fs/namei.c:3668
 do_filp_open+0x21c/0x460 fs/namei.c:3699
 do_sys_openat2+0x13b/0x500 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]
 __x64_sys_openat+0x243/0x290 fs/open.c:1238
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fd2336b1404
RSP: 002b:00007fd232a4fec0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fd2336b1404
RDX: 0000000000000002 RSI: 00007fd232a4ffe0 RDI: 00000000ffffff9c
RBP: 00007fd232a4ffe0 R08: 0000000000000000 R09: 00000000000004a0
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002
R13: 00007fd232a4ffdc R14: 00007fd232a4ffe0 R15: 0000000020000a42
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91c5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3261:
 #0: ffff888024305098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900020a32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1da0 drivers/tty/n_tty.c:2147
2 locks held by syz-executor.0/3571:
 #0: ffff88806ece8150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline]
 #0: ffff88806ece8150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow+0x45/0x70 fs/namei.c:1675
 #1: ffff88806ece85b8 (&fi->mutex){+.+.}-{3:3}, at: fuse_lock_inode+0xcf/0x120 fs/fuse/inode.c:436
2 locks held by syz-executor.0/3591:
 #0: ffff88806ece8150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline]
 #0: ffff88806ece8150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow+0x45/0x70 fs/namei.c:1675
 #1: ffff88806ece85b8 (&fi->mutex){+.+.}-{3:3}, at: fuse_lock_inode+0xcf/0x120 fs/fuse/inode.c:436

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.118-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:570

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
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
* Struck through repros no longer work on HEAD.