[v5.15] INFO: rcu detected stall in mntput_no_expire

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c61bd26ae81a Linux 5.15.160
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13a4cec8980000
kernel config: https://syzkaller.appspot.com/x/.config?x=235f0e81ca937c17
dashboard link: https://syzkaller.appspot.com/bug?extid=22e1de06c56e0dcf7a6f
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/d61a97eef8b9/disk-c61bd26a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ab4908b4b59b/vmlinux-c61bd26a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d818fd46802b/bzImage-c61bd26a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+22e1de...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7740/1:b..l
(detected by 1, t=10502 jiffies, g=47617, q=139)
task:syz-executor.0 state:R running task stack:21088 pid: 7740 ppid: 7728 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
irqentry_exit+0x53/0x80 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627
Code: 2b 00 74 08 4c 89 f7 e8 fc 7c 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90002f57b80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005eaf7c RCX: 1ffff920005eaf1c
RDX: dffffc0000000000 RSI: ffffffff8a8b3c20 RDI: ffffffff8ad8f6c0
RBP: ffffc90002f57ce0 R08: dffffc0000000000 R09: fffffbfff1f7f019
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005eaf78
R13: dffffc0000000000 R14: ffffc90002f57be0 R15: 0000000000000246
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
mntput_no_expire+0xb3/0x770 fs/namespace.c:1169
__fput+0x618/0x890 fs/file_table.c:291
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: 0033:0x7f069fe3adda
RSP: 002b:00007ffd6a8b2bc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f069fe3adda
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffd6a8b2c3c R08: 00007ffd6a8b250c R09: 0079746972756365
R10: 00007ffd6a8b2570 R11: 0000000000000293 R12: 0000000000000032
R13: 000000000004ba80 R14: 000000000004ba6b R15: 0000000000000003
</TASK>
rcu: rcu_preempt kthread starved for 10529 jiffies! g47617 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27000 pid: 15 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
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9546 Comm: syz-executor.2 Not tainted 5.15.160-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:amd_clear_divider+0x0/0x10 arch/x86/kernel/cpu/amd.c:1330
Code: 31 c9 48 83 fe 02 48 89 c6 73 c2 e9 76 ff ff ff 48 85 c0 0f 85 cc fe ff ff 31 c9 e9 66 ff ff ff 0f 0b cc cc cc cc cc cc cc cc <b9> 01 00 00 00 31 c0 31 d2 66 90 c3 cc cc cc cc 41 57 41 56 53 48
RSP: 0018:ffffc90003057f00 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffc90003057f58 RCX: ffffc90003057d03
RDX: 0000000000000000 RSI: ffffffff8a92fba0 RDI: ffffffff8ad8f6c0
RBP: ffffc90003057f48 R08: dffffc0000000000 R09: fffffbfff1bc8cce
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888079853b80 R15: 0000000000000000
FS: 00005555562b8480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002006b000 CR3: 000000001abc8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
arch_exit_to_user_mode arch/x86/include/asm/entry-common.h:94 [inline]
__exit_to_user_mode kernel/entry/common.c:137 [inline]
syscall_exit_to_user_mode+0x71/0x240 kernel/entry/common.c:309
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc50f1f8670
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 3a 9b 04 00 e8 25 78 fa ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007fffd9ab69b8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 000000000004bade RCX: 00007fc50f1d0ee9
RDX: 00007fffd9ab69c0 RSI: 00007fffd9ab6af0 RDI: 0000000000000021
RBP: 00007fffd9ab7070 R08: 0000000000000010 R09: 000000000000109c
R10: 00007fffd9ab7050 R11: 0000000000000246 R12: 000000000004bb10
R13: 00007fc50f2fff8c R14: 00007fffd9ab7050 R15: 0000000000000032
</TASK>


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