[v5.15] INFO: task hung in nilfs_detach_log_writer

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syzbot

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Mar 19, 2024, 6:14:32 PMMar 19
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: b95c01af2113 Linux 5.15.152
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10104006180000
kernel config: https://syzkaller.appspot.com/x/.config?x=b26cb65e5b8ad5c7
dashboard link: https://syzkaller.appspot.com/bug?extid=86ad196992d18d9bb81e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5cd4262a21bb/disk-b95c01af.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/85698e4f8310/vmlinux-b95c01af.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f57a616768d4/bzImage-b95c01af.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+86ad19...@syzkaller.appspotmail.com

INFO: task syz-executor.4:3547 blocked for more than 143 seconds.
Not tainted 5.15.152-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack:19872 pid: 3547 ppid: 1 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
schedule_timeout+0xac/0x300 kernel/time/timer.c:1860
do_wait_for_common+0x2d9/0x480 kernel/sched/completion.c:85
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
__flush_work+0x124/0x1a0 kernel/workqueue.c:3094
nilfs_segctor_destroy fs/nilfs2/segment.c:2768 [inline]
nilfs_detach_log_writer+0x47b/0xbd0 fs/nilfs2/segment.c:2852
nilfs_put_super+0x49/0x150 fs/nilfs2/super.c:498
generic_shutdown_super+0x136/0x2c0 fs/super.c:475
kill_block_super+0x7a/0xe0 fs/super.c:1414
deactivate_locked_super+0xa0/0x110 fs/super.c:335
cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:175
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
__syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f8219c900d7
RSP: 002b:00007ffe4aade288 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f8219c900d7
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffe4aade340
RBP: 00007ffe4aade340 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe4aadf400
R13: 00007f8219cda3b9 R14: 0000000000030f47 R15: 0000000000000009
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by klogd/2950:
#0: ffff8880b9a3a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
2 locks held by getty/3256:
#0: ffff88814b165098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002bab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
1 lock held by syz-executor.4/3547:
#0: ffff888158d6c0e0 (&type->s_umount_key#74){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
3 locks held by kworker/0:7/3589:
#0: ffff888011c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc900030e7d20 ((work_completion)(&sci->sc_iput_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
#2: ffff888158d6c650 (sb_internal#3){.+.+}-{0:0}, at: nilfs_evict_inode+0x163/0x500 fs/nilfs2/inode.c:933

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4715 Comm: kworker/u4:7 Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0x16ec/0x1ff0 kernel/locking/lockdep.c:4915
Code: e9 ff ff 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 39 ea ff ff 48 89 ef e8 93 4d 67 00 48 ba 00 00 00 00 00 fc ff df e9 22 ea ff ff <48> c7 c1 c0 6f 3c 91 80 e1 07 80 c1 03 38 c1 0f 8c 2c ea ff ff 48
RSP: 0018:ffffc90003fbf940 EFLAGS: 00000002
RAX: 0000000000000004 RBX: ffffffff8f8c5f80 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8c91f720
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff88807c6dbb80 R14: 0000000000000002 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00dc67000 CR3: 000000001ee64000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:269
rcu_read_lock include/linux/rcupdate.h:696 [inline]
batadv_nc_process_nc_paths+0xb8/0x350 net/batman-adv/network-coding.c:691
batadv_nc_worker+0x3d4/0x5b0 net/batman-adv/network-coding.c:732
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>


---
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syzbot

unread,
Apr 22, 2024, 5:16:30 PM (10 days ago) Apr 22
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: c52b9710c83d Linux 5.15.156
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17972d20980000
kernel config: https://syzkaller.appspot.com/x/.config?x=567b6ddc38438433
dashboard link: https://syzkaller.appspot.com/bug?extid=86ad196992d18d9bb81e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=128d67cb180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10bc3557180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1bd4b9969373/disk-c52b9710.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/10509e89bd25/vmlinux-c52b9710.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a623a4c52eb5/bzImage-c52b9710.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/b0d5b33284e7/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+86ad19...@syzkaller.appspotmail.com

INFO: task syz-executor170:3540 blocked for more than 143 seconds.
Not tainted 5.15.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor170 state:D stack:25176 pid: 3540 ppid: 3538 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
schedule_timeout+0xac/0x300 kernel/time/timer.c:1890
do_wait_for_common+0x2d9/0x480 kernel/sched/completion.c:85
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
__flush_work+0x124/0x1a0 kernel/workqueue.c:3094
nilfs_segctor_destroy fs/nilfs2/segment.c:2768 [inline]
nilfs_detach_log_writer+0x47b/0xbd0 fs/nilfs2/segment.c:2852
nilfs_put_super+0x49/0x150 fs/nilfs2/super.c:498
generic_shutdown_super+0x136/0x2c0 fs/super.c:475
kill_block_super+0x7a/0xe0 fs/super.c:1414
deactivate_locked_super+0xa0/0x110 fs/super.c:335
cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f56e7d48507
RSP: 002b:00007ffc0f4e0308 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f56e7d48507
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc0f4e03c0
RBP: 00007ffc0f4e03c0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffc0f4e1430
R13: 000055555745a6c0 R14: 431bde82d7b634db R15: 00007ffc0f4e1450
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c91fb20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by klogd/2951:
#0: ffff8880b9b3a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
2 locks held by getty/3257:
#0: ffff88814b581098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002bab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
1 lock held by syz-executor170/3540:
#0: ffff88801ead80e0 (&type->s_umount_key#43){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
3 locks held by kworker/0:2/3602:
#0: ffff888011c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc90002c87d20 ((work_completion)(&sci->sc_iput_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
#2: ffff88801ead8650 (sb_internal#2){.+.+}-{0:0}, at: nilfs_evict_inode+0x163/0x500 fs/nilfs2/inode.c:933

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.156-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 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:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
</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


---
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