[v5.15] INFO: task hung in hfs_mdb_commit

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syzbot

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Jun 10, 2023, 2:34:00 AM6/10/23
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Hello,

syzbot found the following issue on:

HEAD commit: 7349e40704a0 Linux 5.15.116
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10f128ab280000
kernel config: https://syzkaller.appspot.com/x/.config?x=831c3122ac9c9145
dashboard link: https://syzkaller.appspot.com/bug?extid=612ff90eb230c1a4bb5d
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c03c3ad4501/disk-7349e407.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/350c3d79bc87/vmlinux-7349e407.xz
kernel image: https://storage.googleapis.com/syzbot-assets/73a4ed3d5438/bzImage-7349e407.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+612ff9...@syzkaller.appspotmail.com

INFO: task syz-executor.4:3554 blocked for more than 143 seconds.
Not tainted 5.15.116-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack:21048 pid: 3554 ppid: 1 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x4590 kernel/sched/core.c:6372
schedule+0x11b/0x1f0 kernel/sched/core.c:6455
io_schedule+0x88/0x100 kernel/sched/core.c:8472
bit_wait_io+0xe/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit_lock+0xbf/0x1a0 kernel/sched/wait_bit.c:90
out_of_line_wait_on_bit_lock+0x1d0/0x250 kernel/sched/wait_bit.c:117
lock_buffer include/linux/buffer_head.h:402 [inline]
hfs_mdb_commit+0xafb/0xfd0 fs/hfs/mdb.c:325
hfs_sync_fs+0x11/0x20 fs/hfs/super.c:35
sync_filesystem+0xe8/0x220 fs/sync.c:56
generic_shutdown_super+0x6e/0x2c0 fs/super.c:448
kill_block_super+0x7a/0xe0 fs/super.c:1405
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: 0033:0x7f6de8a345d7
RSP: 002b:00007ffe7d9b9f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6de8a345d7
RDX: 00007ffe7d9ba029 RSI: 000000000000000a RDI: 00007ffe7d9ba020
RBP: 00007ffe7d9ba020 R08: 00000000ffffffff R09: 00007ffe7d9b9df0
R10: 00005555566f9873 R11: 0000000000000246 R12: 00007f6de8a8dcdc
R13: 00007ffe7d9bb0e0 R14: 00005555566f9810 R15: 00007ffe7d9bb120
</TASK>
INFO: task kworker/1:6:3598 blocked for more than 143 seconds.
Not tainted 5.15.116-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:6 state:D stack:20064 pid: 3598 ppid: 2 flags:0x00004000
Workqueue: events_long flush_mdb
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x4590 kernel/sched/core.c:6372
schedule+0x11b/0x1f0 kernel/sched/core.c:6455
io_schedule+0x88/0x100 kernel/sched/core.c:8472
bit_wait_io+0xe/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit_lock+0xbf/0x1a0 kernel/sched/wait_bit.c:90
out_of_line_wait_on_bit_lock+0x1d0/0x250 kernel/sched/wait_bit.c:117
lock_buffer include/linux/buffer_head.h:402 [inline]
hfs_mdb_commit+0x117/0xfd0 fs/hfs/mdb.c:271
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2307
worker_thread+0xaca/0x1280 kernel/workqueue.c:2454
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c91c5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3261:
#0: ffff888024803098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900024bb2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1da0 drivers/tty/n_tty.c:2147
1 lock held by syz-executor.4/3554:
#0: ffff88809a2e60e0 (&type->s_umount_key#116){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
2 locks held by kworker/1:6/3598:
#0: ffff888011c65538 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2280
#1: ffffc900043cfd20 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2282
2 locks held by kworker/u4:16/5254:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.116-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3611 Comm: kworker/u4:4 Not tainted 5.15.116-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x60 kernel/kcov.c:197
Code: 89 fb e8 17 00 00 00 48 8b 3d 58 cc 63 0c 48 89 de 5b e9 07 84 48 00 cc cc cc cc cc cc cc 48 8b 04 24 65 48 8b 0d 64 76 82 7e <65> 8b 15 65 76 82 7e f7 c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74
RSP: 0018:ffffc9000447fbe8 EFLAGS: 00000293
RAX: ffffffff89f8e12a RBX: ffff88807ac6cb48 RCX: ffff888018a68000
RDX: 0000000000000000 RSI: ffffffff8a8b0f00 RDI: ffffffff8ad86000
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1bc786e
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000169
R13: dffffc0000000000 R14: ffff88801ca74c80 R15: ffff88801aaa7680
FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf6a6bd000 CR3: 0000000022a23000 CR4: 00000000003506e0
DR0: 0000000000000259 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
rcu_lock_acquire+0xa/0x30 include/linux/rcupdate.h:269
rcu_read_lock include/linux/rcupdate.h:696 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0xc1/0x5b0 net/batman-adv/network-coding.c:723
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2307
worker_thread+0xaca/0x1280 kernel/workqueue.c:2454
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>


---
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If the bug is already fixed, let syzbot know by replying with:
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If you want to change bug's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
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If you want to undo deduplication, reply with:
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syzbot

unread,
Sep 18, 2023, 2:33:50 AM9/18/23
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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