rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (10499 ticks this GP) idle=d25/1/0x4000000000000000 softirq=8460/8460 fqs=2
(t=10500 jiffies g=9389 q=203)
rcu: rcu_preempt kthread starved for 10495 jiffies! g9389 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:28064 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4790 Comm: syz.4.102 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__lock_release kernel/locking/lockdep.c:5330 [inline]
RIP: 0010:lock_release+0x2e7/0x870 kernel/locking/lockdep.c:5643
Code: 4c 89 e7 48 89 d3 e8 e8 b5 5f 00 48 89 da 49 8b 1c 24 4c 8b 74 24 18 49 81 c6 e0 0a 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 <74> 0e 4c 89 f7 49 89 d4 e8 3c b6 5f 00 4c 89 e2 49 89 1e 3b 54 24
RSP: 0018:ffffc900037bfd80 EFLAGS: 00000046
RAX: 1ffff11004cda514 RBX: ffffffffffffffff RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffff8880266d24e8 RDI: ffff8880266d28b0
RBP: ffffc900037bfe88 R08: dffffc0000000000 R09: fffffbfff1ad33a6
R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: ffff8880266d28b0
R13: dffffc0000000000 R14: ffff8880266d28a0 R15: 1ffff920006f7fbc
FS: 00007faf573476c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000007927b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
do_write_seqcount_end include/linux/seqlock.h:565 [inline]
vtime_user_enter+0x1f0/0x2d0 kernel/sched/cputime.c:718
__context_tracking_enter+0x60/0x90 kernel/context_tracking.c:82
user_enter_irqoff include/linux/context_tracking.h:41 [inline]
__exit_to_user_mode kernel/entry/common.c:136 [inline]
syscall_exit_to_user_mode+0x3c/0x40 kernel/entry/common.c:309
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7faf59108e80
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 8a 54 08 00 e8 05 8f f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007faf57346b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007faf59336fa8 RCX: 00007faf590e0749
RDX: 00007faf57346b40 RSI: 00007faf57346c70 RDI: 0000000000000021
RBP: 00007faf59336fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faf59337038 R14: 00007fff9e533aa0 R15: 00007fff9e533b88
NMI backtrace for cpu 0
CPU: 0 PID: 4783 Comm: syz.2.99 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x6d8/0x1110 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:1685 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
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:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline]
RIP: 0010:trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:57 [inline]
RIP: 0010:fpregs_activate+0x5f/0x1a0 arch/x86/include/asm/fpu/internal.h:451
Code: 07 77 58 e8 a3 29 4c 00 41 89 de c1 eb 06 48 8d 3c dd 28 9d 69 8d be 08 00 00 00 e8 3b 93 90 00 31 f6 4c 0f a3 35 99 fa 3d 0c <0f> 92 c3 40 0f 92 c6 bf 02 00 00 00 e8 d0 2b 4c 00 84 db 74 10 e8
RSP: 0018:ffffc9000337faf8 EFLAGS: 00000247
RAX: ffffffff812ba201 RBX: 0000000000000000 RCX: ffffffff812ba285
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d699d28
RBP: ffffc9000337fcf0 R08: dffffc0000000000 R09: fffffbfff1ad33a6
R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
fpregs_mark_activate+0x23/0x80 arch/x86/kernel/fpu/core.c:429
restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:299 [inline]
__fpu_restore_sig arch/x86/kernel/fpu/signal.c:334 [inline]
fpu__restore_sig+0x780/0xf50 arch/x86/kernel/fpu/signal.c:466
restore_sigcontext arch/x86/kernel/signal.c:139 [inline]
__ia32_sys_rt_sigreturn+0x649/0x790 arch/x86/kernel/signal.c:674
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7efdb6c20749
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:00007ffcff93cf38 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00000000000222b3 RCX: 00007efdb6c20749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efdb6e76fac
RBP: 0000000000000032 R08: 00383bc9cc668154 R09: 0000000cff93d22f
R10: 00007ffcff93d030 R11: 0000000000000246 R12: 00007efdb6e76fac
R13: 00007ffcff93d030 R14: 00000000000222e5 R15: 00007ffcff93d050