syzbot


INFO: task hung in nilfs_segctor_thread (5)

Status: auto-obsoleted due to no activity on 2025/09/27 08:54
Subsystems: nilfs
[Documentation on labels]
First crash: 92d, last: 92d
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in nilfs_segctor_thread nilfs2 1 C 41 958d 1059d 0/1 upstream: reported C repro on 2022/11/05 03:06
linux-5.15 INFO: task hung in nilfs_segctor_thread (2) 1 2 425d 505d 0/3 auto-obsoleted due to no activity on 2024/11/07 22:53
upstream INFO: task hung in nilfs_segctor_thread (3) nilfs 1 138 411d 436d 0/29 auto-obsoleted due to no activity on 2024/10/22 18:08
upstream INFO: task hung in nilfs_segctor_thread nilfs 1 C error 94 880d 1054d 22/29 fixed on 2023/06/08 14:41
linux-5.15 INFO: task hung in nilfs_segctor_thread 1 3 891d 903d 0/3 auto-obsoleted due to no activity on 2023/08/20 05:29
upstream INFO: task hung in nilfs_segctor_thread (4) nilfs 1 1 331d 331d 0/29 auto-obsoleted due to no activity on 2025/01/31 15:40
linux-4.14 INFO: task hung in nilfs_segctor_thread nilfs2 1 C 1 956d 956d 0/1 upstream: reported C repro on 2023/02/16 07:03
upstream INFO: task hung in nilfs_segctor_thread (2) nilfs 1 C inconclusive 98 478d 588d 26/29 fixed on 2024/07/09 19:14
linux-6.1 INFO: task hung in nilfs_segctor_thread 1 40 360d 505d 0/3 auto-obsoleted due to no activity on 2024/12/12 18:46
linux-5.15 INFO: task hung in nilfs_segctor_thread (3) 1 1 299d 299d 0/3 auto-obsoleted due to no activity on 2025/03/13 18:17

Sample crash report:
INFO: task segctord:10425 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc3-syzkaller-00329-gdfba48a70cb6 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:segctord        state:D stack:28424 pid:10425 tgid:10425 ppid:2      task_flags:0x200040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 nilfs_transaction_lock+0x253/0x4c0 fs/nilfs2/segment.c:357
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2569 [inline]
 nilfs_segctor_thread+0x6ec/0xe00 fs/nilfs2/segment.c:2684
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
3 locks held by kworker/u8:1/13:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:6/1141:
2 locks held by getty/5582:
 #0: ffff88803101b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/1:3/5873:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000435fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000435fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff88806b587240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180 drivers/net/netdevsim/fib.c:1490
1 lock held by dhcpcd/7223:
 #0: ffff88806ce8a608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #0: ffff88806ce8a608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff88806ce8a608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1391
2 locks held by syz.4.476/10421:
1 lock held by segctord/10425:
 #0: ffff8880562152a0 (&nilfs->ns_segctor_sem){++++}-{4:4}, at: nilfs_transaction_lock+0x253/0x4c0 fs/nilfs2/segment.c:357
3 locks held by syz-executor/10932:
2 locks held by syz-executor/11718:
 #0: ffff888031a180e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888031a180e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888031a180e0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8e570a88 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444
1 lock held by syz.5.761/13476:
 #0: ffff888031a180e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
 #0: ffff888031a180e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz-executor/13779:
 #0: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #0: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998
2 locks held by syz.4.803/13986:
1 lock held by syz.6.804/13992:
 #0: ffff88805560a0e0 (&type->s_umount_key#61/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970 fs/super.c:345
3 locks held by dhcpcd-run-hook/14008:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc3-syzkaller-00329-gdfba48a70cb6 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 13992 Comm: syz.6.804 Not tainted 6.16.0-rc3-syzkaller-00329-gdfba48a70cb6 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:asm_exc_page_fault+0x4/0x30 arch/x86/include/asm/idtentry.h:623
Code: 74 24 28 ff 74 24 28 ff 74 24 28 ff 74 24 28 e8 42 07 00 00 48 89 c4 48 89 e7 e8 87 8c 5f 0a e9 72 08 00 00 90 90 f3 0f 1e fa <0f> 01 ca fc e8 23 07 00 00 48 89 c4 48 89 e7 48 8b 74 24 78 48 c7
RSP: 0018:ffffc90003327870 EFLAGS: 00040083
RAX: ffffffff8206774c RBX: 00000000001ff800 RCX: 0000000000080000
RDX: ffffc9001b402000 RSI: 00000000000077b4 RDI: 00000000000077b5
RBP: dffffc0000000001 R08: ffff88804e959e00 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000002 R12: 00002000000dc000
R13: 00002000000dc000 R14: 00002000000008c0 R15: 00002000002000c0
FS:  00007fd4ce6646c0(0000) GS:ffff888125d84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000dc000 CR3: 000000001daae000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
RIP: 0010:fault_in_readable+0x8e/0x130 mm/gup.c:2227
Code: a9 00 00 00 0f 01 cb 0f ae e8 4d 85 f6 40 0f 95 c5 4c 89 ff 4c 89 f6 e8 d0 d8 b9 ff 4d 39 f7 0f 97 c0 40 84 c5 74 43 4d 89 f5 <41> 8a 45 00 88 44 24 07 49 81 e5 00 f0 ff ff 4d 8d a5 00 10 00 00
RSP: 0018:ffffc900033278a8 EFLAGS: 00050283
 fault_in_iov_iter_readable+0x1b4/0x2f0 lib/iov_iter.c:94
 iomap_write_iter fs/iomap/buffered-io.c:974 [inline]
 iomap_file_buffered_write+0x3fc/0x980 fs/iomap/buffered-io.c:1058
 xfs_file_buffered_write+0x201/0x890 fs/xfs/xfs_file.c:981
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x54b/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd4cd78e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd4ce664038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd4cd9b5fa0 RCX: 00007fd4cd78e929
RDX: 00000000fffffdef RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fd4cd810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd4cd9b5fa0 R15: 00007ffcdea35ef8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/29 08:46 upstream dfba48a70cb6 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in nilfs_segctor_thread
* Struck through repros no longer work on HEAD.