syzbot


INFO: task hung in do_unlinkat (4)

Status: auto-obsoleted due to no activity on 2023/04/08 02:53
Subsystems: exfat
[Documentation on labels]
First crash: 669d, last: 562d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in do_unlinkat (2) 1 594d 594d 0/1 auto-obsoleted due to no activity on 2023/03/27 07:50
android-49 INFO: task hung in do_unlinkat 5 2146d 2258d 0/3 auto-closed as invalid on 2019/02/24 11:49
upstream INFO: task hung in do_unlinkat (5) kernfs bcachefs 50 20d 41d 0/27 upstream: reported on 2024/06/02 14:09
upstream INFO: task hung in do_unlinkat (2) fs 4 1252d 1252d 0/27 auto-closed as invalid on 2021/05/17 08:41
upstream INFO: task hung in do_unlinkat exfat 34 2006d 2243d 0/27 closed as dup on 2018/10/27 13:26
upstream INFO: task hung in do_unlinkat (3) fs 2 970d 1013d 0/27 closed as invalid on 2022/02/07 19:19
linux-4.19 INFO: task hung in do_unlinkat 1 724d 724d 0/1 auto-obsoleted due to no activity on 2022/11/17 10:56
linux-5.15 INFO: task hung in do_unlinkat 1 62d 62d 0/3 upstream: reported on 2024/05/12 15:06

Sample crash report:
INFO: task syz-executor.5:32442 blocked for more than 143 seconds.
      Not tainted 6.2.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:23912 pid:32442 ppid:5102   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x995/0xe20 kernel/sched/core.c:6555
 schedule+0xcb/0x190 kernel/sched/core.c:6631
 rwsem_down_write_slowpath+0xfc1/0x1480 kernel/locking/rwsem.c:1190
 __down_write_common kernel/locking/rwsem.c:1305 [inline]
 __down_write kernel/locking/rwsem.c:1314 [inline]
 down_write_nested+0x23f/0x280 kernel/locking/rwsem.c:1673
 inode_lock_nested include/linux/fs.h:791 [inline]
 do_unlinkat+0x23d/0x930 fs/namei.c:4303
 __do_sys_unlink fs/namei.c:4368 [inline]
 __se_sys_unlink fs/namei.c:4366 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4366
 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+0x63/0xcd
RIP: 0033:0x7f086368c0a9
RSP: 002b:00007f0864325168 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007f08637ac120 RCX: 00007f086368c0a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000100
RBP: 00007f08636e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff88ba6c2f R14: 00007f0864325300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
 #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7f2/0xdb0
 #1: ffffc900000e7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d326e90 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d327690 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
2 locks held by kworker/1:1/26:
 #0: ffff888012872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7f2/0xdb0
 #1: ffffc90000a1fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264
1 lock held by khungtaskd/28:
 #0: ffffffff8d326cc0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by udevd/4433:
2 locks held by getty/4750:
 #0: ffff88814a873098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900015a02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x53b/0x1650 drivers/tty/n_tty.c:2177
1 lock held by syz-executor.0/5105:
 #0: ffffffff8d32c338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #0: ffffffff8d32c338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x384/0x860 kernel/rcu/tree_exp.h:946
2 locks held by kworker/u4:8/10344:
 #0: ffff8880b993a1d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x110 kernel/sched/core.c:537
 #1: ffffc9000ab37d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264
4 locks held by kworker/u4:9/31971:
 #0: ffff888145234938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7f2/0xdb0
 #1: ffffc9001a68fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264
 #2: ffff88823bce60e0 (&type->s_umount_key#105){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:415
 #3: ffff888037f0c0e0 (&sbi->s_lock#2){+.+.}-{3:3}, at: exfat_write_inode+0x65/0x110 fs/exfat/inode.c:93
6 locks held by syz-executor.5/32433:
2 locks held by syz-executor.5/32442:
 #0: ffff88823bce6460 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:508
 #1: ffff888035a51cb0 (&sb->s_type->i_mutex_key#35/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
 #1: ffff888035a51cb0 (&sb->s_type->i_mutex_key#35/1){+.+.}-{3:3}, at: do_unlinkat+0x23d/0x930 fs/namei.c:4303
1 lock held by syz-executor.2/3278:
 #0: ffffffff8d32c338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #0: ffffffff8d32c338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x860 kernel/rcu/tree_exp.h:946
2 locks held by syz-executor.4/3338:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46f/0x4f0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ba/0x420 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xcd5/0xd20 kernel/hung_task.c:377
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7694 Comm: kworker/1:18 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:hlock_class kernel/locking/lockdep.c:239 [inline]
RIP: 0010:mark_lock+0xc8/0x350 kernel/locking/lockdep.c:4612
Code: de a2 12 0f 72 24 48 c7 c0 80 90 fd 91 48 c1 e8 03 42 8a 04 28 84 c0 0f 85 25 02 00 00 83 3d be 21 92 10 00 74 4a 31 db eb 0f <48> 8d 04 5b 48 c1 e0 06 48 8d 98 80 70 4d 90 48 83 c3 50 48 89 d8
RSP: 0018:ffffc900161a7960 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 00000000000006ea RCX: ffffffff816b6e9a
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff907e1258
RBP: 0000000000000006 R08: dffffc0000000000 R09: fffffbfff20fc24c
R10: fffffbfff20fc24c R11: 1ffffffff20fc24b R12: ffff88802a2b8a88
R13: dffffc0000000000 R14: 0000000000000040 R15: ffff88802a2b8a88
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f27753821b8 CR3: 000000000d08e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __lock_acquire+0xc61/0x1f60 kernel/locking/lockdep.c:5009
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:350 [inline]
 wg_ratelimiter_gc_entries+0x5c/0x4a0 drivers/net/wireguard/ratelimiter.c:63
 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/28 21:48 upstream 1b929c02afd3 44712fbc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in do_unlinkat
2022/12/04 05:00 upstream c2bf05db6c78 e080de16 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in do_unlinkat
2022/09/23 06:00 upstream dc164f4fb00a 0042f2b4 .config console log report info [disk image] [vmlinux] ci2-upstream-fs INFO: task hung in do_unlinkat
2022/09/13 13:55 upstream e839a756012b a08652b0 .config console log report info ci-upstream-kasan-gce-root INFO: task hung in do_unlinkat
* Struck through repros no longer work on HEAD.