rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P26292/1:b..l
(detected by 1, t=10502 jiffies, g=166949, q=34)
task:syz.6.5332 state:R running task stack:27744 pid:26292 ppid: 24931 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
preempt_schedule_notrace+0xca/0x110 kernel/sched/core.c:6631
preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
rcu_is_watching+0x72/0xa0 kernel/rcu/tree.c:1124
trace_lock_acquire include/trace/events/lock.h:13 [inline]
lock_acquire+0xcd/0x3f0 kernel/locking/lockdep.c:5594
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
dput+0x35/0x1a0 fs/dcache.c:879
__fput+0x5ee/0x930 fs/file_table.c:319
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x61e/0x20a0 kernel/exit.c:883
do_group_exit+0x12e/0x300 kernel/exit.c:997
get_signal+0x6ca/0x12c0 kernel/signal.c:2900
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
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+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f57395e99a9
RSP: 002b:00007f57373ee0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f5739811248 RCX: 00007f57395e99a9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5739811248
RBP: 00007f5739811240 R08: 00007ffdf63df9b7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f573981124c
R13: 0000000000000001 R14: 00007ffdf63df8d0 R15: 00007ffdf63df9b8
rcu: rcu_preempt kthread starved for 10500 jiffies! g166949 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27136 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 19286 Comm: syz-executor Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xb88/0xd70 kernel/smp.c:969
Code: b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 a6 46 0b 00 83 e3 01 75 07 e8 3c 43 0b 00 eb 43 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 41 f7
RSP: 0018:ffffc90003cafba0 EFLAGS: 00000293
RAX: ffffffff816c810b RBX: 0000000000000001 RCX: ffff888074831dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003cafce0 R08: dffffc0000000000 R09: fffffbfff1ff6e2e
R10: fffffbfff1ff6e2e R11: 1ffffffff1ff6e2d R12: ffff8880b9042a08
R13: 1ffff11017208541 R14: ffff8880b913b380 R15: 0000000000000000
on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
invalidate_bdev+0x8a/0xb0 block/bdev.c:86
ext4_put_super+0x8cc/0xe00 fs/ext4/super.c:1255
generic_shutdown_super+0x130/0x300 fs/super.c:475
kill_block_super+0x7c/0xe0 fs/super.c:1427
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x418/0x4d0 fs/namespace.c:1139
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/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+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5f0f145cd7
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc7a09cbb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5f0f1c6b55 RCX: 00007f5f0f145cd7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc7a09cc70
RBP: 00007ffc7a09cc70 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc7a09dd00
R13: 00007f5f0f1c6b55 R14: 0000000000154409 R15: 00007ffc7a09dd40