[v6.1] INFO: rcu detected stall in sys_statfs

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ae9f2a70d69e Linux 6.1.93
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1128a19c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1d7ac9fef66f54aa
dashboard link: https://syzkaller.appspot.com/bug?extid=41dcc2cbfdb30499fe09
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/b6a79d8f90ec/disk-ae9f2a70.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f1b3e75b81f1/vmlinux-ae9f2a70.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80fc2213e3e5/bzImage-ae9f2a70.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+41dcc2...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9001/1:b..l
(detected by 0, t=10502 jiffies, g=39909, q=58 ncpus=2)
task:modprobe state:R running task stack:23880 pid:9001 ppid:9 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x142d/0x4550 kernel/sched/core.c:6558
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:203
Code: e8 25 00 00 00 0f 0b 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 58 01 e9 0c 48 89 de 5b e9 e7 a8 56 00 cc cc cc cc cc cc cc <48> 8b 04 24 65 48 8b 0d 24 dc 77 7e 65 8b 15 25 dc 77 7e f7 c2 00
RSP: 0018:ffffc90011c0f930 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffff888028595940
RDX: ffff888028595940 RSI: ffffffff8b3d4500 RDI: ffffffff8b3d44c0
RBP: fffffffffffffffe R08: ffffffff81f539ee R09: ffffed1004fa0ad0
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90011c0fa80
R13: 0000000000000000 R14: dffffc0000000000 R15: dffffc0000000000
rcu_read_unlock include/linux/rcupdate.h:820 [inline]
leave_rcu+0x90/0x160 fs/namei.c:675
terminate_walk+0x28d/0x420 fs/namei.c:691
path_lookupat+0x328/0x450 fs/namei.c:2496
filename_lookup+0x251/0x600 fs/namei.c:2508
user_path_at_empty+0x3e/0x60 fs/namei.c:2907
user_path_at include/linux/namei.h:57 [inline]
user_statfs+0xd5/0x450 fs/statfs.c:103
__do_sys_statfs fs/statfs.c:195 [inline]
__se_sys_statfs fs/statfs.c:192 [inline]
__x64_sys_statfs+0xe4/0x1a0 fs/statfs.c:192
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f89858ac68a
RSP: 002b:00007ffdf7ca1558 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: ffffffffffffffda RBX: 00007f89857d14f8 RCX: 00007f89858ac68a
RDX: ffffffffffffff80 RSI: 00007ffdf7ca15d0 RDI: 00007f89857c972a
RBP: 00007f89857c972a R08: 0000000000000000 R09: 000000000000000d
R10: 00007ffdf7ca1380 R11: 0000000000000246 R12: 00007ffdf7ca15d0
R13: 00007ffdf7ca1748 R14: 00007ffdf7ca1770 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10179 jiffies! g39909 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:26776 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x142d/0x4550 kernel/sched/core.c:6558
schedule+0xbf/0x180 kernel/sched/core.c:6634
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:113 [inline]
RIP: 0010:acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:572
Code: 35 f5 f6 48 83 e3 08 0f 85 0b 01 00 00 4c 8d 74 24 20 e8 14 f4 fb f6 0f 1f 44 00 00 e8 6a 31 f5 f6 0f 00 2d 33 fe b1 00 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 9b b1 4c f7
RSP: 0018:ffffffff8ce07b20 EFLAGS: 000002d3
RAX: ffffffff8a9561a6 RBX: 0000000000000000 RCX: ffffffff8cebd800
RDX: 0000000000000000 RSI: ffffffff8aec0240 RDI: ffffffff8b3d4520
RBP: ffffffff8ce07bb0 R08: ffffffff8a956188 R09: fffffbfff19d7b01
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff19c0f64
R13: ffff8880157ad804 R14: ffffffff8ce07b40 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f89858ac683 CR3: 000000001972b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
</IRQ>
<TASK>
acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:709
cpuidle_enter_state+0x516/0xf80 drivers/cpuidle/cpuidle.c:239
cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:356
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:236 [inline]
do_idle+0x3ce/0x680 kernel/sched/idle.c:303
cpu_startup_entry+0x3d/0x60 kernel/sched/idle.c:401
rest_init+0x2da/0x300 init/main.c:734
arch_call_rest_init+0xa/0xa init/main.c:894
start_kernel+0x496/0x53f init/main.c:1141
secondary_startup_64_no_verify+0xcf/0xdb
</TASK>


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