rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21/1:b..l P9/1:b..l
(detected by 0, t=10502 jiffies, g=6437, q=712)
task:kworker/u4:0 state:R running task stack:24264 pid: 9 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__test_set_page_writeback+0xc04/0xe70 mm/page-writeback.c:2887
Code: ff e8 50 0e d7 ff 48 ff cb e9 9d f7 ff ff e8 43 0e d7 ff e8 be 79 00 08 48 85 db 0f 84 d1 fc ff ff e8 30 0e d7 ff fb 4c 89 e7 06 00 00 00 e8 52 8d 06 00 4c 89 e7 e8 7a f1 20 00 48 c7 44 24
RSP: 0018:ffffc90000ce6d40 EFLAGS: 00000293
RAX: ffffffff81a0b310 RBX: 0000000000000200 RCX: ffff88813fed0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0001c8a080
RBP: ffffc90000ce6eb0 R08: dffffc0000000000 R09: fffffbfff1ff362e
R10: fffffbfff1ff362e R11: 1ffffffff1ff362d R12: ffffea0001c8a080
R13: 1ffff9200019cdb4 R14: 0000000000000000 R15: 0000000000000000
ext4_bio_write_page+0x293/0x1f90 fs/ext4/page-io.c:-1
mpage_submit_page+0x17a/0x210 fs/ext4/inode.c:2113
mpage_map_and_submit_buffers fs/ext4/inode.c:2361 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2500 [inline]
ext4_writepages+0x1a1f/0x2d20 fs/ext4/inode.c:2829
do_writepages+0x48d/0x6d0 mm/page-writeback.c:2386
__writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1647
writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2001
wb_writeback+0x455/0xb90 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+0xaaa/0xe60 fs/fs-writeback.c:2288
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
task:kworker/1:0 state:R running task stack:22336 pid: 21 ppid: 2 flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:seqcount_lockdep_reader_access+0x17b/0x1c0 include/linux/seqlock.h:106
Code: f9 4d 85 e4 75 16 e8 54 4c 69 f9 eb 15 e8 4d 4c 69 f9 e8 c8 b7 92 01 4d 85 e4 74 ea e8 3e 4c 69 f9 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00
RSP: 0018:ffffc90000db7a20 EFLAGS: 00000293
RAX: ffffffff880e7502 RBX: 0000000000000000 RCX: ffff888016a91dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000db7ad0 R08: dffffc0000000000 R09: fffffbfff1ff362c
R10: fffffbfff1ff362c R11: 1ffffffff1ff362b R12: 0000000000000200
R13: ffff88807ced5980 R14: 1ffff920001b6f44 R15: dffffc0000000000
nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:338 [inline]
gc_worker+0x2e2/0x13a0 net/netfilter/nf_conntrack_core.c:1472
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 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 10491 jiffies! g6437 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=3877
rcu: rcu_preempt kthread starved for 10492 jiffies! g6437 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28032 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 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.184-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:3932 [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:default_idle+0xb/0x10 arch/x86/kernel/process.c:723
Code: bf 48 89 df e8 16 c9 12 f8 eb b5 e8 4f be f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d a7 53 5b 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8be07dc8 EFLAGS: 000002c6
RAX: d6f41b179d92d800 RBX: ffffffff8bebc3c0 RCX: d6f41b179d92d800
RDX: 0000000000000001 RSI: ffffffff8a0b11c0 RDI: ffffffff8a59a700
RBP: ffffffff8be07ef8 R08: dffffc0000000000 R09: ffffed101720765a
R10: ffffed101720765a R11: 1ffff11017207659 R12: ffffffff8d68aaa8
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff17d7878
default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
cpuidle_idle_call kernel/sched/idle.c:194 [inline]
do_idle+0x21b/0x5b0 kernel/sched/idle.c:306
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
start_kernel+0x486/0x530 init/main.c:1140
secondary_startup_64_no_verify+0xb1/0xbb