rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=3854/1/0x4000000000000000 softirq=42230/42230 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=50977, q=3049 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10488 Comm: syz.9.1092 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:122 [inline]
RIP: 0010:lock_acquire+0x122/0x410 kernel/locking/lockdep.c:5730
Code: 65 8b 05 e9 8f 9b 7e 85 c0 0f 85 2e 01 00 00 65 4c 8b 35 b1 bb 9c 7e 49 81 c6 dc 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 f3 01 00 00 41 83 3e 00 0f 85 01 01 00 00 48 c7 84 24
RSP: 0000:ffffc900041f7420 EFLAGS: 00000803
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 58d8a76ac82d8f00
RDX: 0000000000000000 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: ffffc900041f7528 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 1ffff9200083ee90
R13: ffffffff8cd2ff20 R14: ffff888027458adc R15: dffffc0000000000
FS:  00007fb5434696c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2cfed6 CR3: 00000000762f6000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xc0/0xa20 kernel/events/ring_buffer.c:273
 __perf_event_output kernel/events/core.c:7975 [inline]
 perf_event_output_forward+0x22b/0x3a0 kernel/events/core.c:7993
 __perf_event_overflow+0x447/0x630 kernel/events/core.c:9718
 perf_swevent_overflow kernel/events/core.c:9794 [inline]
 perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
 perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10344
 perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10268
 perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
 trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 8b b3 eb f6 e8 26 3a 1c f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0000:ffffc900041f7da0 EFLAGS: 00000286
RAX: 58d8a76ac82d8f00 RBX: 0000000000000000 RCX: 58d8a76ac82d8f00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc900041f7e50 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff9200083efb4
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 82 02 f5 08 65 48 8b 05 da 2b 91 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 d5 69 19 00 fb 41 f6 c6 08 <74> 05 e8 59 2a fd 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 28 ea
RSP: 0000:ffffc900041f7f10 EFLAGS: 00000202
RAX: 58d8a76ac82d8f00 RBX: ffffc900041f7f58 RCX: 58d8a76ac82d8f00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: 0000000000000000 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff888027458000
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0033:0x7fb54258f749
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:00007fb543469038 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fb5427e5fa0 RCX: 00007fb54258f749
RDX: 00002000000006c0 RSI: 0000000000005452 RDI: 0000000000000003
RBP: 00007fb542613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb5427e6038 R14: 00007fb5427e5fa0 R15: 00007ffd27df6318
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g50977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=29306
rcu: rcu_preempt kthread starved for 10502 jiffies! g50977 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:26056 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10488 Comm: syz.9.1092 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x8/0x80 kernel/kcov.c:320
Code: 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d b0 20 7e 7e 65 8b 15 b1 20 7e 7e 81 e2 00 01 ff 00 74
RSP: 0000:ffffc90000007ae8 EFLAGS: 00000046
RAX: ffffffff81acd49a RBX: 0000000000010000 RCX: ffff888027458000
RDX: 0000000000010000 RSI: 0000000000010000 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: dffffc0000000001
R13: dffffc0000000000 R14: ffff8880b8e00000 R15: dffffc0000000000
FS:  00007fb5434696c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2cfed6 CR3: 00000000762f6000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 interrupt_context_level include/linux/preempt.h:97 [inline]
 get_recursion_context kernel/events/internal.h:214 [inline]
 perf_swevent_get_recursion_context+0xaa/0x150 kernel/events/core.c:9947
 perf_trace_buf_alloc+0x59/0x290 kernel/trace/trace_event_perf.c:410
 perf_trace_lock+0x193/0x380 include/trace/events/lock.h:50
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x857/0x8b0 kernel/locking/lockdep.c:5765
 __raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:239 [inline]
 _raw_read_unlock_irqrestore+0x71/0x110 kernel/locking/spinlock.c:268
 kill_fasync_rcu fs/fcntl.c:997 [inline]
 kill_fasync+0x228/0x4b0 fs/fcntl.c:1011
 perf_event_wakeup+0x2ee/0x380 kernel/events/core.c:6794
 perf_pending_irq+0x165/0x5e0 kernel/events/core.c:6890
 irq_work_single+0xd5/0x230 kernel/irq_work.c:221
 irq_work_run_list kernel/irq_work.c:252 [inline]
 irq_work_run+0x156/0x2e0 kernel/irq_work.c:261
 __sysvec_irq_work+0x98/0x380 arch/x86/kernel/irq_work.c:22
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x9c/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 8b b3 eb f6 e8 26 3a 1c f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0000:ffffc900041f7da0 EFLAGS: 00000286
RAX: 58d8a76ac82d8f00 RBX: 0000000000000000 RCX: 58d8a76ac82d8f00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc900041f7e50 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff9200083efb4
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 82 02 f5 08 65 48 8b 05 da 2b 91 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 d5 69 19 00 fb 41 f6 c6 08 <74> 05 e8 59 2a fd 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 28 ea
RSP: 0000:ffffc900041f7f10 EFLAGS: 00000202
RAX: 58d8a76ac82d8f00 RBX: ffffc900041f7f58 RCX: 58d8a76ac82d8f00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: 0000000000000000 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff888027458000
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0033:0x7fb54258f749
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:00007fb543469038 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fb5427e5fa0 RCX: 00007fb54258f749
RDX: 00002000000006c0 RSI: 0000000000005452 RDI: 0000000000000003
RBP: 00007fb542613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb5427e6038 R14: 00007fb5427e5fa0 R15: 00007ffd27df6318
 </TASK>