[v6.1] INFO: task hung in ocfs2_sync_fs (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c2fda4b3f577 Linux 6.1.156
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17883542580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=461b6cef59759882f703
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/10e802f3fcb6/disk-c2fda4b3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/66b88bca821f/vmlinux-c2fda4b3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5f220b7a420e/bzImage-c2fda4b3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+461b6c...@syzkaller.appspotmail.com

INFO: task syz-executor:4268 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:22144 pid:4268 ppid:1 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
jbd2_log_wait_commit+0x29d/0x4a0 fs/jbd2/journal.c:710
ocfs2_sync_fs+0x217/0x310 fs/ocfs2/super.c:412
sync_filesystem+0x1be/0x220 fs/sync.c:66
generic_shutdown_super+0x6b/0x340 fs/super.c:474
kill_block_super+0x7c/0xe0 fs/super.c:1470
deactivate_locked_super+0x93/0xf0 fs/super.c:332
cleanup_mnt+0x463/0x4f0 fs/namespace.c:1182
task_work_run+0x1ca/0x250 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2b1bb901f7
RSP: 002b:00007ffe06daec08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f2b1bc11d7d RCX: 00007f2b1bb901f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe06daecc0
RBP: 00007ffe06daecc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe06dafd50
R13: 00007f2b1bc11d7d R14: 0000000000061687 R15: 00007ffe06dafd90
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
3 locks held by ksoftirqd/0/15:
1 lock held by khungtaskd/28:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4025:
#0: ffff88802fc76098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by syz-executor/4268:
#0: ffff8880246b00e0 (&type->s_umount_key#77){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
2 locks held by udevd/4417:
5 locks held by kworker/u4:18/5068:
#0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9001ce1fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd34710 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:594
#3: ffffffff8dd413e8 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xc8/0x360 net/ipv4/ip_tunnel.c:1166
#4: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#4: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962
2 locks held by kworker/1:17/5922:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9000e10fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by jbd2/loop0-75/7456:
2 locks held by syz-executor/7646:
#0: ffff888079a5a0e0 (&type->s_umount_key#66){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
#1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
1 lock held by syz.4.1289/8802:
1 lock held by syz.5.1290/8804:
#0: ffffffff8cb30780 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
1 lock held by udevadm/8834:
1 lock held by sed/8836:
#0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 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+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8827 Comm: syz.1.1291 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_rdp_cpu_online kernel/rcu/tree.c:236 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0xa8/0x120 kernel/rcu/tree.c:776
Code: 42 80 3c 30 00 74 05 e8 b6 ec 65 00 4c 8b 7b 20 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 98 ec 65 00 <48> 8b 1b 48 83 c3 70 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48
RSP: 0018:ffffc900001e0828 EFLAGS: 00000246
RAX: 1ffff110171e7733 RBX: ffff8880b8f3b998 RCX: 07e355267d810c00
RDX: ffff888046a0bb80 RSI: ffffffff8adef000 RDI: ffff8880b8f3b9a0
RBP: 0000000000000001 R08: 0000000000000007 R09: 00000000001e0a00
R10: ffffed10046ba2b8 R11: 1ffff110046ba2b7 R12: 0000000000000038
R13: ffff8880235d2af0 R14: dffffc0000000000 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdc3183cd8 CR3: 000000007e7b9000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
rcu_read_lock_held+0x1a/0x40 kernel/rcu/update.c:309
mac80211_hwsim_addr_iter+0x87/0x1a0 drivers/net/wireless/mac80211_hwsim.c:1224
__iterate_interfaces+0x243/0x500 net/mac80211/util.c:788
ieee80211_iterate_active_interfaces_atomic+0xd7/0x170 net/mac80211/util.c:824
mac80211_hwsim_addr_match drivers/net/wireless/mac80211_hwsim.c:1247 [inline]
mac80211_hwsim_tx_frame_no_nl+0xe2a/0x1330 drivers/net/wireless/mac80211_hwsim.c:1734
mac80211_hwsim_tx_frame+0x1b5/0x200 drivers/net/wireless/mac80211_hwsim.c:2058
mac80211_hwsim_beacon_tx+0x61e/0xae0 drivers/net/wireless/mac80211_hwsim.c:2121
__iterate_interfaces+0x243/0x500 net/mac80211/util.c:788
ieee80211_iterate_active_interfaces_atomic+0xd7/0x170 net/mac80211/util.c:824
mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
__run_hrtimer kernel/time/hrtimer.c:1747 [inline]
__hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1811
hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc900035978a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 07e355267d810c00
RDX: 0000000000000000 RSI: ffffffff8a8c1680 RDI: ffffffff8adef020
RBP: ffffc900035979c0 R08: dffffc0000000000 R09: fffffbfff215c44b
R10: fffffbfff215c44b R11: 1ffffffff215c44a R12: 0000000000000001
R13: 1ffff920006b2f20 R14: 0000000000000246 R15: dffffc0000000000
__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:351 [inline]
task_lock include/linux/sched/task.h:206 [inline]
exit_fs+0x52/0x140 fs/fs_struct.c:101
do_exit+0x8f8/0x2400 kernel/exit.c:876
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
get_signal+0x1272/0x1350 kernel/signal.c:2871
arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6234d8eec9
Code: Unable to access opcode bytes at 0x7f6234d8ee9f.
RSP: 002b:00007f6235b46038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: fffffffffffffe00 RBX: 00007f6234fe5fa0 RCX: 00007f6234d8eec9
RDX: 000000000000006f RSI: 0000000000000084 RDI: 0000000000000004
RBP: 00007f6234e11f91 R08: 00002000000002c0 R09: 0000000000000000
R10: 0000200000000280 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6234fe6038 R14: 00007f6234fe5fa0 R15: 00007ffd80189668
</TASK>


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