rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P154/1:b..l
(detected by 1, t=10502 jiffies, g=13617, q=89)
task:kworker/u4:2 state:R running task stack:21352 pid: 154 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
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:constant_test_bit arch/x86/include/asm/bitops.h:207 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
RIP: 0010:PageSlab include/linux/page-flags.h:356 [inline]
RIP: 0010:__page_memcg+0xa5/0x140 include/linux/memcontrol.h:406
Code: 74 08 4c 89 ff e8 fb f0 fa ff 49 8b 07 49 83 fc ff 74 60 49 89 df a8 01 75 51 4c 89 ff be 08 00 00 00 e8 6e f2 fa ff 4c 89 f8 <48> c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 c8 f0 fa ff 49 f7 07
RSP: 0000:ffffc900020269c8 EFLAGS: 00000256
RAX: ffffea0001be7480 RBX: ffffea0001be7480 RCX: ffffffff81c14252
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffea0001be7480
RBP: 1ffffd400037ce91 R08: dffffc0000000000 R09: fffff9400037ce91
R10: fffff9400037ce91 R11: 1ffffd400037ce90 R12: 00fff00000002017
R13: dffffc0000000000 R14: ffff888016a7c000 R15: ffffea0001be7480
page_memcg include/linux/memcontrol.h:459 [inline]
lock_page_memcg+0x137/0x410 mm/memcontrol.c:2052
__test_set_page_writeback+0x9e/0xe70 mm/page-writeback.c:2844
ext4_bio_write_page+0x293/0x1f90 fs/ext4/page-io.c:-1
mpage_submit_page+0x17a/0x210 fs/ext4/inode.c:2113
mpage_process_page_bufs+0x6d8/0x8b0 fs/ext4/inode.c:2227
mpage_prepare_extent_to_map+0xb7d/0xf70 fs/ext4/inode.c:2655
ext4_writepages+0xa09/0x2d20 fs/ext4/inode.c:2783
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
rcu: rcu_preempt kthread timer wakeup didn't happen for 10546 jiffies! g13617 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=7219
rcu: rcu_preempt kthread starved for 10552 jiffies! g13617 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:28032 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
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: 5342 Comm: syz.3.34 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 3e 1d aa f7 48 89 df e8 06 f2 aa f7 e8 c1 8c cb f7 fb bf 01 00 00 00 46 15 9f f7 65 8b 05 27 13 50 76 85 c0 74 02 5b c3 e8 d4 1d 4e
RSP: 0018:ffffc9000385fbc0 EFLAGS: 00000282
RAX: 1d44ee0e4013ee00 RBX: ffff88806edc5340 RCX: 1d44ee0e4013ee00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: 0000000000000001
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100ddb8a69
R10: ffffed100ddb8a69 R11: 1ffff1100ddb8a68 R12: ffff88806edc5340
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000004000000
spin_unlock_irq include/linux/spinlock.h:413 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
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+0xee/0x180 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: 0033:0x7f56045f1c29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5603c61038 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f5604838fa0 RCX: 00007f56045f1c29
RDX: 0000200000000180 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 00007f5604674e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5604839038 R14: 00007f5604838fa0 R15: 00007ffc1b164d98
sched: RT throttling activated
hrtimer: interrupt took 1114160019 ns