rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=e67c/0/0x1 softirq=88509/88510 fqs=2
(detected by 0, t=10502 jiffies, g=138301, q=69 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x1b/0x60 kernel/kcov.c:216
Code: 89 de 5b e9 77 62 50 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d 14 41 80 7e 65 8b 15 15 41 80 7e 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00
RSP: 0018:ffffc900001e0d10 EFLAGS: 00000006
RAX: ffffffff81724c4f RBX: ffff8880798f1340 RCX: ffff888017741e00
RDX: 0000000000010000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: 0000000000000002 R08: ffffffff96ea6feb R09: 1ffffffff2dd4dfd
R10: dffffc0000000000 R11: fffffbfff2dd4dfe R12: dffffc0000000000
R13: ffff8880798f1340 R14: ffff8880b8f2a7c0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2dd21ff8 CR3: 00000000446e3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
cpu_max_bits_warn include/linux/cpumask.h:110 [inline]
cpumask_check include/linux/cpumask.h:117 [inline]
cpumask_test_cpu include/linux/cpumask.h:444 [inline]
cpu_online include/linux/cpumask.h:1030 [inline]
trace_hrtimer_start include/trace/events/timer.h:203 [inline]
debug_activate kernel/time/hrtimer.c:503 [inline]
enqueue_hrtimer+0x7f/0x410 kernel/time/hrtimer.c:1097
__run_hrtimer kernel/time/hrtimer.c:1768 [inline]
__hrtimer_run_queues+0x63e/0xc90 kernel/time/hrtimer.c:1815
hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 17 47 99 f7 e9 44 ff ff ff e8 fd 03 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 57 93 4c 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:ffffc90000177de8 EFLAGS: 000002c6
RAX: 7f52c4680af0b500 RBX: ffffffff8a3a18b7 RCX: 7f52c4680af0b500
RDX: 0000000000000001 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf5de0
RBP: ffffc90000177f20 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888017741e00 R15: 1ffff9200002efc8
default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a2/0x680 kernel/sched/idle.c:323
cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422
start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xcf/0xdb
rcu: rcu_preempt kthread starved for 10498 jiffies! g138301 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27888 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 47 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0x1148/0x1250 kernel/smp.c:998
Code: 41 8b 1f 89 de 83 e6 01 31 ff e8 73 ff 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 0a e8 ff fb 0a 00 e9 34 ff ff ff f3 90 <41> 0f b6 04 1c 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 17 ff ff ff
RSP: 0018:ffffc90000b87800 EFLAGS: 00000293
RAX: ffffffff81773243 RBX: dffffc0000000000 RCX: ffff88801de91e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000b87960 R08: ffffffff90b10247 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: 1ffff110171e8219
R13: ffff8880b8e3bdc0 R14: 0000000000000001 R15: ffff8880b8f410c8
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5175a27dac CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774
text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
static_key_enable+0x16/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295