[v5.15] INFO: task hung in ext4_stop_mmpd (2)

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Jul 4, 2024, 9:23:22 AM (3 days ago) Jul 4
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Hello,

syzbot found the following issue on:

HEAD commit: 4878aadf2d15 Linux 5.15.161
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=178c0a69980000
kernel config: https://syzkaller.appspot.com/x/.config?x=875d98826c53bf16
dashboard link: https://syzkaller.appspot.com/bug?extid=1dff897d2e020878c508
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/f227a150ea92/disk-4878aadf.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6cfc50bf8b4e/vmlinux-4878aadf.xz
kernel image: https://storage.googleapis.com/syzbot-assets/23f7adc3c761/bzImage-4878aadf.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1dff89...@syzkaller.appspotmail.com

INFO: task syz-executor:3510 blocked for more than 143 seconds.
Not tainted 5.15.161-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:20376 pid: 3510 ppid: 1 flags:0x00004004
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
kthread_stop+0x178/0x580 kernel/kthread.c:664
ext4_stop_mmpd+0x43/0xb0 fs/ext4/mmp.c:263
ext4_put_super+0xac5/0x1060 fs/ext4/super.c:1266
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: 0033:0x7fba992cbf07
RSP: 002b:00007ffff9841e38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fba99338515 RCX: 00007fba992cbf07
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffff9841ef0
RBP: 00007ffff9841ef0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffff9842fc0
R13: 00007fba99338515 R14: 000000000002990d R15: 000000000000000f
</TASK>
INFO: task kmmpd-loop4:5138 blocked for more than 144 seconds.
Not tainted 5.15.161-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kmmpd-loop4 state:D stack:27320 pid: 5138 ppid: 2 flags:0x00004000
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
percpu_rwsem_wait+0x3e1/0x470 kernel/locking/percpu-rwsem.c:160
__percpu_down_read+0xd0/0x100 kernel/locking/percpu-rwsem.c:174
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
__sb_start_write include/linux/fs.h:1811 [inline]
sb_start_write include/linux/fs.h:1881 [inline]
write_mmp_block+0x2f0/0x390 fs/ext4/mmp.c:66
kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c91fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3261:
#0: ffff88814aec5098 (&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/3505:
#0: ffff88801b1f40e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by syz-executor/3510:
#0: ffff88807bfc80e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by kworker/1:10/3578:
#0: ffff8880b9b3a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
2 locks held by kworker/u4:6/3599:
1 lock held by syz-executor/3925:
#0: ffff88807c5a20e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by syz-executor/4151:
#0: ffff888077b640e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by kmmpd-loop4/5138:
#0: ffff88807bfc8460 (sb_writers#5){++++}-{0:0}, at: kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
1 lock held by syz-executor/5203:
#0: ffff8880769a40e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by kmmpd-loop1/5208:
#0: ffff888077b64460 (sb_writers#5){++++}-{0:0}, at: kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
1 lock held by kmmpd-loop0/5279:
#0: ffff88807c5a2460 (sb_writers#5){++++}-{0:0}, at: kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
1 lock held by kmmpd-loop3/5340:
#0: ffff88801b1f4460 (sb_writers#5){++++}-{0:0}, at: kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
1 lock held by syz.1.531/5501:
#0: ffff888077b640e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by syz.4.608/5712:
#0: ffff88807bfc80e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by syz.1.697/5953:
#0: ffff888077b640e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by syz.3.816/6295:
#0: ffff88801b1f40e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by syz.0.1088/7044:
#0: ffff88807c5a20e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by kmmpd-loop2/7213:
#0: ffff8880769a4460 (sb_writers#5){++++}-{0:0}, at: kmmpd+0x292/0xa90 fs/ext4/mmp.c:248
1 lock held by syz.4.1153/7227:
#0: ffff88807bfc80e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837
1 lock held by syz.3.1223/7454:
#0: ffff88801b1f40e0 (&type->s_umount_key#32){++++}-{3:3}, at: user_get_super+0x11a/0x250 fs/super.c:837

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3766 Comm: kworker/u4:7 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: phy31 ieee80211_iface_work
RIP: 0010:get_freelist mm/slub.c:2844 [inline]
RIP: 0010:___slab_alloc+0x285/0xe10 mm/slub.c:2939
Code: 00 00 44 89 6c 24 10 4c 8b 28 4d 85 ed 0f 85 eb 0a 00 00 83 3d ff 3b 1b 0c 00 74 34 49 8b 1f 48 83 c3 20 e8 4d ed 54 08 89 c5 <83> f8 08 0f 83 10 08 00 00 48 03 1c ed 00 f8 35 8c 48 89 df be ff
RSP: 0018:ffffc90003017718 EFLAGS: 00000086
RAX: 0000000000000000 RBX: 000000000003df60 RCX: ffffffff81636252
RDX: dffffc0000000000 RSI: ffffffff8ad8f720 RDI: ffffffff8ad8f6e0
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1f7f219
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea00007e1600
R13: 0000000000000000 R14: ffffffff7fff0000 R15: ffff888011c41dc0
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6556542ab8 CR3: 0000000016c3a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
__slab_alloc mm/slub.c:3095 [inline]
slab_alloc_node mm/slub.c:3186 [inline]
slab_alloc mm/slub.c:3228 [inline]
__kmalloc+0x1c9/0x300 mm/slub.c:4403
kmalloc include/linux/slab.h:596 [inline]
kzalloc include/linux/slab.h:721 [inline]
ieee802_11_parse_elems_crc+0xb3/0x1130 net/mac80211/util.c:1478
ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2238 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
ieee80211_ibss_rx_queued_mgmt+0x380/0x2af0 net/mac80211/ibss.c:1643
ieee80211_iface_process_skb net/mac80211/iface.c:1441 [inline]
ieee80211_iface_work+0x78f/0xcc0 net/mac80211/iface.c:1495
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
</TASK>


---
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