rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4740/1:b..l
(detected by 1, t=10624 jiffies, g=12333, q=1328)
task:kworker/u4:6 state:R running task stack:20056 pid: 4740 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6552
preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6577
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_set_page_writeback+0x8ab/0xf10 mm/page-writeback.c:2881
ext4_bio_write_page+0x2b3/0x1f80 fs/ext4/page-io.c:-1
mpage_submit_page+0x18d/0x230 fs/ext4/inode.c:2112
mpage_process_page_bufs+0x6c8/0x8b0 fs/ext4/inode.c:2226
mpage_prepare_extent_to_map+0xc9d/0x1150 fs/ext4/inode.c:2654
ext4_writepages+0xcd0/0x3d10 fs/ext4/inode.c:2782
do_writepages+0x481/0x730 mm/page-writeback.c:2386
__writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647
writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001
wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106
wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
wb_do_writeback fs/fs-writeback.c:2259 [inline]
wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288
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 timer wakeup didn't happen for 3864 jiffies! g12333 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=7094
rcu: rcu_preempt kthread starved for 3865 jiffies! g12333 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27000 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
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:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 4545 Comm: syz-execprog Not tainted 5.15.180-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:1690 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1816
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+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0033:0x425bfe
Code: c9 eb 0f 48 83 c4 50 5d c3 49 ff c1 d1 ea 49 83 c0 08 49 83 f9 08 7d c6 4c 39 c3 76 c1 0f ba e2 00 73 e6 4d 8d 14 00 4d 8b 12 <66> 90 4d 85 d2 74 d8 4c 89 4c 24 40 4c 89 54 24 38 4c 89 44 24 48
RSP: 002b:000000c0014d5dc8 EFLAGS: 00000213
RAX: 0000000003c068c0 RBX: 0000000000040000 RCX: 00007fbb94a54000
RDX: 0000000000000019 RSI: 0000000000000000 RDI: 000000c000067268
RBP: 000000c0014d5e18 R08: 0000000000005958 R09: 0000000000000003
R10: 0000000002d26d20 R11: 0000000004045268 R12: 000000c0014d5ee8
R13: 0000000000000000 R14: 000000c00057b340 R15: 000000000000001d