rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1425/1:b..l
(detected by 1, t=10502 jiffies, g=7433, q=52)
task:kworker/u4:4 state:R running task stack:24000 pid: 1425 ppid: 2 flags:0x00004000
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
Call Trace:
context_switch kernel/sched/core.c:5029 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6375
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6551
preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6576
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
test_clear_page_writeback+0x98a/0xd30 mm/page-writeback.c:2826
end_page_writeback+0x2a6/0x690 mm/filemap.c:1603
ext4_finish_bio+0x751/0x8b0 fs/ext4/page-io.c:145
ext4_release_io_end+0xdf/0x2c0 fs/ext4/page-io.c:160
ext4_end_io_end fs/ext4/page-io.c:194 [inline]
ext4_do_flush_completed_IO fs/ext4/page-io.c:259 [inline]
ext4_end_io_rsv_work+0x5d6/0x6e0 fs/ext4/page-io.c:273
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:287
rcu: rcu_preempt kthread starved for 10527 jiffies! g7433 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:27288 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5029 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6375
schedule+0x11b/0x1f0 kernel/sched/core.c:6458
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:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 4338 Comm: syz.2.18 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
__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_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3932 [inline]
rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
update_process_times+0x196/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1688 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x13b/0x4b0 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:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x37/0x240 kernel/entry/common.c:114
Code: 49 89 fe 48 8b 7c 24 30 e8 46 f6 ff ff e9 8d 01 00 00 e9 91 01 00 00 e8 e7 12 47 f7 e8 d2 10 47 f7 fb 65 4c 8b 3d 49 65 c2 75 <49> 8b 5f 08 f6 c3 3f 0f 84 ce 00 00 00 f6 c3 20 74 17 4c 89 f7 e8
RSP: 0018:ffffc900031efef8 EFLAGS: 00000282
RAX: b527393461410300 RBX: ffffc900031eff30 RCX: ffffffff96a95f03
RDX: dffffc0000000000 RSI: ffffffff8aab2a60 RDI: ffffffff8af9fa80
RBP: ffffc900031eff48 R08: ffffffff81871b70 R09: fffffbfff1c153f6
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 000000000000000f R14: ffffc900031eff58 R15: ffff88802c60bb80
do_syscall_64+0x1e/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f46c0347359
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007f46be1f2b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f46c05c4088 RCX: 00007f46c0347359
RDX: 00007f46be1f2b40 RSI: 00007f46be1f2c70 RDI: 0000000000000011
RBP: 00007f46c05c4080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f46c05c408c
R13: 0000000000000000 R14: 00007ffcde05d270 R15: 00007ffcde05d358