rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=4e94/1/0x4000000000000000 softirq=25805/25806 fqs=1
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7478/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=15185, q=1856 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7518 Comm: syz.4.657 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:do_raw_spin_lock+0x2a/0x2b0 kernel/locking/spinlock_debug.c:114
Code: f3 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 41 56 41 55 41 54 55 53 48 89 fb 48 83 c7 04 48 83 ec 68 48 c7 44 24 08 b3 8a b5 41 <48> 8d 6c 24 08 48 c7 44 24 10 13 1b aa 8d 48 c1 ed 03 48 c7 44 24
RSP: 0018:ffffc90000a08cf8 EFLAGS: 00000092
RAX: dffffc0000000000 RBX: ffff8880202f32a8 RCX: 1d89dd3d985ee89f
RDX: 0000000000000000 RSI: ffffffff8daa7b4b RDI: ffff8880202f32ac
RBP: ffff888028720000 R08: 00000000ffffffff R09: 00000000ffffffff
R10: 0000000000000000 R11: ffff8880274f54b0 R12: ffff8880b8528440
R13: 0000000000000000 R14: ffff8880202f3300 R15: ffffffff8980aae0
FS: 00007f4e51d6c6c0(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4e51d6bf98 CR3: 0000000033357000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
spin_lock include/linux/spinlock.h:351 [inline]
advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:930
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 c6 1d 1f f6 48 89 df e8 7e 70 1f f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 85 73 0f f6 65 8b 05 2e c9 37 08 85 c0 74 16 5b
RSP: 0018:ffffc9000f9c7c98 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff8880b8428440 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffffff8dacdbe3 RDI: ffffffff8bf2b380
RBP: 0000000000000283 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088afd7 R11: ffff8880274f54b0 R12: 0000000000000000
R13: 1bc16d4d66998c0d R14: dffffc0000000000 R15: ffff8880b8428440
clock_was_set+0x599/0x870 kernel/time/hrtimer.c:965
do_settimeofday64+0x364/0x550 kernel/time/timekeeping.c:1460
do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195
__do_sys_clock_settime kernel/time/posix-timers.c:1131 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1115 [inline]
__x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1115
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4e50f8f749
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:00007f4e51d6c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007f4e511e5fa0 RCX: 00007f4e50f8f749
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007f4e51013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4e511e6038 R14: 00007f4e511e5fa0 R15: 00007ffe48d2ef78
task:syz.3.640 state:R running task stack:26504 pid:7478 tgid:7476 ppid:5812 task_flags:0x400140 flags:0x00080006
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:55 [inline]
RIP: 0010:stack_access_ok+0x30/0x200 arch/x86/kernel/unwind_orc.c:409
Code: 00 fc ff df 41 57 41 56 4c 8d 77 08 41 55 41 54 49 89 d4 4c 89 f2 55 48 c1 ea 03 48 89 f5 53 48 89 fb 48 83 ec 08 80 3c 02 00 <0f> 85 94 01 00 00 4c 8d 6b 10 4c 8b 7b 08 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc9000e5a72c8 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc9000e5a7378 RCX: ffffffff915b7706
RDX: 1ffff92001cb4e70 RSI: ffffc9000e5a7b60 RDI: ffffc9000e5a7378
RBP: ffffc9000e5a7b60 R08: ffffffff915b770a R09: 000000005635be4b
R10: 0000000000000002 R11: 000000000003a0e0 R12: 0000000000000008
R13: ffffc9000e5a7378 R14: ffffc9000e5a7380 R15: ffffc9000e5a73ac
deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline]
unwind_next_frame+0xb7d/0x20b0 arch/x86/kernel/unwind_orc.c:600
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__do_kmalloc_node mm/slub.c:5657 [inline]
__kmalloc_noprof+0x33d/0x910 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kmalloc_array_noprof include/linux/slab.h:1003 [inline]
io_ring_buffers_peek+0x818/0xb00 io_uring/kbuf.c:268
io_buffers_peek+0x31d/0x430 io_uring/kbuf.c:366
io_recv_buf_select io_uring/net.c:1126 [inline]
io_recv+0x8ff/0x12e0 io_uring/net.c:1191
__io_issue_sqe+0xe8/0x7c0 io_uring/io_uring.c:1792
io_issue_sqe+0x85/0x1410 io_uring/io_uring.c:1815
io_queue_sqe io_uring/io_uring.c:2042 [inline]
io_req_task_submit+0x184/0x2a0 io_uring/io_uring.c:1434
io_handle_tw_list+0x4e7/0x580 io_uring/io_uring.c:1121
tctx_task_work_run+0x55/0x2d0 io_uring/io_uring.c:1181
tctx_task_work+0x7a/0xd0 io_uring/io_uring.c:1199
task_work_run+0x150/0x240 kernel/task_work.c:233
get_signal+0x1d0/0x26d0 kernel/signal.c:2807
arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f36d4b8f749
RSP: 002b:00007f36d5a11038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000000800 RBX: 00007f36d4de5fa0 RCX: 00007f36d4b8f749
RDX: 000000000000f4f5 RSI: 0000000000003516 RDI: 0000000000000005
RBP: 00007f36d4c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36d4de6038 R14: 00007f36d4de5fa0 R15: 00007ffc5dc87988
rcu: rcu_preempt kthread starved for 10500 jiffies! g15185 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:27768 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 1138 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xe02/0x15e0 kernel/smp.c:877
Code: 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 35 5b 0c 00 f3 90 41 0f b6 45 00 <40> 38 c5 7c 08 84 c0 0f 85 b6 05 00 00 8b 43 08 31 ff 83 e0 01 41
RSP: 0018:ffffc900042c7808 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8540cc0 RCX: ffffffff81b28b81
RDX: ffff888027af8000 RSI: ffffffff81b28b5b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffff888027af8b30 R12: dffffc0000000000
R13: ffffed10170a8199 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881248f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3e2cd4 CR3: 000000000e184000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline]
smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2921
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
jump_label_update+0x376/0x550 kernel/jump_label.c:919
static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate mm/kfence/core.c:874 [inline]
toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:866
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246