syzbot


INFO: task hung in vfs_unlink (4)

Status: auto-obsoleted due to no activity on 2024/01/16 15:08
Subsystems: fs
[Documentation on labels]
First crash: 343d, last: 183d
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 18d 30d 0/3 upstream: reported on 2024/03/19 12:40
linux-6.1 INFO: task hung in vfs_unlink (2) 1 147d 147d 0/3 auto-obsoleted due to no activity on 2024/03/02 11:45
linux-4.14 INFO: task hung in vfs_unlink (2) 1 1095d 1095d 0/1 auto-closed as invalid on 2021/08/17 05:41
linux-4.14 INFO: task hung in vfs_unlink 8 1340d 1582d 0/1 auto-closed as invalid on 2020/12/15 00:37
linux-4.19 INFO: task hung in vfs_unlink (4) 1 526d 526d 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 1349d 1411d 0/1 auto-closed as invalid on 2020/12/05 18:54
upstream INFO: task hung in vfs_unlink (3) ext4 1 444d 444d 0/26 auto-obsoleted due to no activity on 2023/04/30 04:19
linux-5.15 INFO: task hung in vfs_unlink 29 31d 388d 0/3 upstream: reported on 2023/03/26 16:46
upstream INFO: task hung in vfs_unlink ext4 32 1362d 1639d 0/26 auto-closed as invalid on 2020/11/23 01:14
linux-6.1 INFO: task hung in vfs_unlink 2 336d 347d 0/3 auto-obsoleted due to no activity on 2023/08/26 02:49
linux-4.19 INFO: task hung in vfs_unlink 6 1540d 1665d 0/1 auto-closed as invalid on 2020/05/28 17:30
linux-4.19 INFO: task hung in vfs_unlink (3) 1 988d 988d 0/1 auto-closed as invalid on 2021/12/01 23:35
upstream INFO: task hung in vfs_unlink (2) fs 1 621d 621d 0/26 auto-closed as invalid on 2022/10/05 08:13

Sample crash report:
INFO: task syz-fuzzer:5016 blocked for more than 143 seconds.
      Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-fuzzer      state:D stack:24512 pid:5016  ppid:5010   flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6710
 schedule+0xe7/0x1b0 kernel/sched/core.c:6786
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6845
 rwsem_down_write_slowpath+0x53e/0x1290 kernel/locking/rwsem.c:1178
 __down_write_common kernel/locking/rwsem.c:1306 [inline]
 __down_write kernel/locking/rwsem.c:1315 [inline]
 down_write+0x1d3/0x200 kernel/locking/rwsem.c:1574
 inode_lock include/linux/fs.h:771 [inline]
 vfs_unlink+0xd3/0x900 fs/namei.c:4318
 do_unlinkat+0x3da/0x6d0 fs/namei.c:4395
 __do_sys_unlinkat fs/namei.c:4438 [inline]
 __se_sys_unlinkat fs/namei.c:4431 [inline]
 __x64_sys_unlinkat+0xc1/0x130 fs/namei.c:4431
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x403ace
RSP: 002b:000000c000b93508 EFLAGS: 00000202 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000000403ace
RDX: 0000000000000000 RSI: 000000c0212e45a0 RDI: 0000000000000013
RBP: 000000c000b93548 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000005a
R13: ffffffffffffffff R14: 000000c013470680 R15: 000000c0001d1800
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
 #0: ffffffff8c9a67f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522
1 lock held by rcu_tasks_trace/14:
 #0: ffffffff8c9a64f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522
1 lock held by khungtaskd/28:
 #0: ffffffff8c9a7400 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6615
2 locks held by getty/4783:
 #0: ffff88814ae3b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015c02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfcb/0x1480 drivers/tty/n_tty.c:2187
3 locks held by syz-fuzzer/5016:
 #0: ffff88814be82410 (sb_writers#4){.+.+}-{0:0}, at: do_unlinkat+0x1ca/0x6d0 fs/namei.c:4376
 #1: ffff888082dede00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:806 [inline]
 #1: ffff888082dede00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x27c/0x6d0 fs/namei.c:4380
 #2: ffff888074feb600 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:771 [inline]
 #2: ffff888074feb600 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: vfs_unlink+0xd3/0x900 fs/namei.c:4318
3 locks held by kworker/u4:1/21812:
1 lock held by syz-executor.1/23362:
1 lock held by syz-executor.1/23363:
1 lock held by syz-executor.1/23364:
1 lock held by syz-executor.1/23645:
7 locks held by syz-executor.1/23650:
1 lock held by syz-executor.4/23661:
1 lock held by syz-executor.4/23776:
4 locks held by syz-executor.3/23783:
1 lock held by syz-executor.3/23817:
1 lock held by syz-executor.4/23843:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x2ac/0x310 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf29/0x11b0 kernel/hung_task.c:379
 kthread+0x33a/0x430 kernel/kthread.c:389
 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 23830 Comm: kworker/u4:0 Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x20 kernel/kcov.c:304
Code: 66 0f 1f 44 00 00 f3 0f 1e fa 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 b8 fe ff ff 0f 1f 84 00 00 00 00 00 f3 0f 1e fa <48> 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 9a fe ff ff 66 2e 0f 1f
RSP: 0018:ffffc9000bd1fba8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff88807878c620 RCX: 0000000000000001
RDX: 1ffff1100597c158 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000000000c4 R08: 0000000000000000 R09: fffffbfff2309dd0
R10: ffffffff9184ee87 R11: 0000000000000000 R12: ffff88802946bd80
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c000b55b88 CR3: 000000002adff000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:750 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x186/0x10f0 net/batman-adv/network-coding.c:719
 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600
 worker_thread+0x687/0x1110 kernel/workqueue.c:2751
 kthread+0x33a/0x430 kernel/kthread.c:389
 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/16 01:02 upstream 4853c74bd7ab 39990d51 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in vfs_unlink
2023/10/18 15:08 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 78124b0c1d10 342b9c55 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in vfs_unlink
2023/10/10 01:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 19af4a4ed414 3c53c7d9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in vfs_unlink
2023/07/13 08:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e40939bbfc68 86081196 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in vfs_unlink
2023/06/15 23:49 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci f86b85033b8c 757d26ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in vfs_unlink
2023/05/11 08:31 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 14f8db1c0f9a 0fbd49f4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in vfs_unlink
* Struck through repros no longer work on HEAD.