syzbot


INFO: task hung in vfs_unlink (2)

Status: auto-obsoleted due to no activity on 2024/03/02 11:45
Reported-by: syzbot+14f1764576ca2d1d60ef@syzkaller.appspotmail.com
First crash: 180d, last: 180d
Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in vfs_unlink (3) 2 52d 63d 0/3 upstream: reported on 2024/03/19 12:40
linux-4.14 INFO: task hung in vfs_unlink (2) 1 1128d 1128d 0/1 auto-closed as invalid on 2021/08/17 05:41
linux-4.14 INFO: task hung in vfs_unlink 8 1374d 1615d 0/1 auto-closed as invalid on 2020/12/15 00:37
linux-4.19 INFO: task hung in vfs_unlink (4) 1 560d 560d 0/1 auto-obsoleted due to no activity on 2023/03/09 01:26
linux-4.19 INFO: task hung in vfs_unlink (2) 2 1383d 1445d 0/1 auto-closed as invalid on 2020/12/05 18:54
upstream INFO: task hung in vfs_unlink (3) ext4 1 477d 477d 0/26 auto-obsoleted due to no activity on 2023/04/30 04:19
linux-5.15 INFO: task hung in vfs_unlink 29 65d 422d 0/3 upstream: reported on 2023/03/26 16:46
upstream INFO: task hung in vfs_unlink ext4 32 1396d 1672d 0/26 auto-closed as invalid on 2020/11/23 01:14
linux-6.1 INFO: task hung in vfs_unlink 2 370d 381d 0/3 auto-obsoleted due to no activity on 2023/08/26 02:49
linux-4.19 INFO: task hung in vfs_unlink 6 1574d 1699d 0/1 auto-closed as invalid on 2020/05/28 17:30
linux-4.19 INFO: task hung in vfs_unlink (3) 1 1022d 1022d 0/1 auto-closed as invalid on 2021/12/01 23:35
upstream INFO: task hung in vfs_unlink (4) fs 6 216d 376d 0/26 auto-obsoleted due to no activity on 2024/01/16 15:08
upstream INFO: task hung in vfs_unlink (2) fs 1 654d 654d 0/26 auto-closed as invalid on 2022/10/05 08:13

Sample crash report:
INFO: task syz-fuzzer:4251 blocked for more than 143 seconds.
      Not tainted 6.1.63-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-fuzzer      state:D stack:0     pid:4251  ppid:4217   flags:0x00000008
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xee4/0x1c98 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 rwsem_down_write_slowpath+0xc80/0x156c kernel/locking/rwsem.c:1189
 __down_write_common kernel/locking/rwsem.c:1314 [inline]
 __down_write kernel/locking/rwsem.c:1323 [inline]
 down_write+0x84/0x88 kernel/locking/rwsem.c:1574
 inode_lock include/linux/fs.h:756 [inline]
 vfs_unlink+0xd8/0x508 fs/namei.c:4242
 do_unlinkat+0x4c8/0x708 fs/namei.c:4321
 __do_sys_unlinkat fs/namei.c:4364 [inline]
 __se_sys_unlinkat fs/namei.c:4357 [inline]
 __arm64_sys_unlinkat+0xcc/0xfc fs/namei.c:4357
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff8000159f4df0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
 #0: ffff8000159f55f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
 #0: ffff8000159f4c20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:305
2 locks held by syslogd/3829:
3 locks held by klogd/3833:
2 locks held by getty/3982:
 #0: ffff0000d5d4b098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001bca02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188
3 locks held by syz-fuzzer/4251:
 #0: ffff0000d7a12460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff000129312218 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
 #1: ffff000129312218 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x2cc/0x708 fs/namei.c:4304
 #2: ffff00012930e850 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #2: ffff00012930e850 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_unlink+0xd8/0x508 fs/namei.c:4242
4 locks held by syz-executor.2/27420:
1 lock held by syz-executor.4/27443:

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/11/23 11:45 linux-6.1.y 69e434a1cb21 fc59b78e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in vfs_unlink
* Struck through repros no longer work on HEAD.