syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=d22c/1/0x4000000000000000 softirq=33480/33481 fqs=44
rcu: 	(t=10501 jiffies g=34705 q=1752 ncpus=2)
rcu: rcu_preempt kthread starved for 10413 jiffies! g34705 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:26728 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9436 Comm: syz.6.859 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:perf_trace_lock+0x30/0x380 include/trace/events/lock.h:50
Code: 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 00 00 49 89 ff 65 48 8b 04 25 28 00 00 00 48 89 84 24 a0 00 00 00 <49> bc 00 00 00 00 00 fc ff df 48 c7 44 24 40 b3 8a b5 41 48 c7 44
RSP: 0018:ffffc900001ef620 EFLAGS: 00000082
RAX: 05cfe0d09bcbe500 RBX: ffff888024529898 RCX: dffffc0000000000
RDX: ffffffff81ac5794 RSI: ffffffff8cd2ff20 RDI: ffffffff8cbfb200
RBP: ffffc900001ef710 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: ffffffff81ac5794
R13: dffffc0000000000 R14: ffffffff81ac5794 R15: ffffffff8cbfb200
FS:  00007f9af31f66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9af2dd2f98 CR3: 000000005edef000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x857/0x8b0 kernel/locking/lockdep.c:5765
 rcu_lock_release include/linux/rcupdate.h:344 [inline]
 rcu_read_unlock include/linux/rcupdate.h:819 [inline]
 __perf_event_output kernel/events/core.c:7984 [inline]
 perf_event_output_forward+0x2f7/0x3a0 kernel/events/core.c:7993
 __perf_event_overflow+0x447/0x630 kernel/events/core.c:9718
 perf_swevent_hrtimer+0x3bc/0x530 kernel/events/core.c:11188
 __run_hrtimer kernel/time/hrtimer.c:1750 [inline]
 __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:unwind_next_frame+0x1c42/0x2970 arch/x86/kernel/unwind_orc.c:664
Code: 89 37 48 8b 44 24 18 42 0f b6 04 28 84 c0 48 8b 5c 24 60 0f 85 a3 0a 00 00 41 8b 2c 24 89 ef 44 8b b4 24 8c 00 00 00 44 89 f6 <e8> b9 d2 4a 00 44 39 f5 0f 85 a1 00 00 00 48 8b 44 24 68 42 80 3c
RSP: 0018:ffffc900001eff98 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc900001f00a0 RCX: ffff88801be93c00
RDX: 0000000000000100 RSI: 0000000000000002 RDI: 0000000000000002
RBP: 0000000000000002 R08: ffff88801be93c00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001f0068
R13: dffffc0000000000 R14: 0000000000000002 R15: ffffffff8f556760
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915
 packet_rcv+0x5dd/0x13d0 net/packet/af_packet.c:2218
 deliver_skb net/core/dev.c:2264 [inline]
 dev_queue_xmit_nit+0x5f6/0xbb0 net/core/dev.c:2334
 xmit_one net/core/dev.c:3615 [inline]
 dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3635
 __dev_queue_xmit+0x1a64/0x35a0 net/core/dev.c:4425
 dev_queue_xmit include/linux/netdevice.h:3113 [inline]
 hsr_xmit net/hsr/hsr_forward.c:380 [inline]
 hsr_forward_do net/hsr/hsr_forward.c:471 [inline]
 hsr_forward_skb+0x1317/0x2120 net/hsr/hsr_forward.c:624
 send_hsr_supervision_frame+0x5fb/0xb90 net/hsr/hsr_device.c:346
 hsr_announce+0x192/0x340 net/hsr/hsr_device.c:402
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x36/0x60 kernel/kcov.c:216
Code: f0 24 7e 7e 65 8b 15 f1 24 7e 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 00 <83> fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc
RSP: 0018:ffffc90003727d38 EFLAGS: 00000246
RAX: ffffffff81ad2015 RBX: 0000000000000002 RCX: ffff88801be93c00
RDX: 0000000000000002 RSI: 00000000ffffffff RDI: 00000000ffffffff
RBP: ffffc90003727f10 R08: ffff888030db1383 R09: 1ffff110061b6270
R10: dffffc0000000000 R11: ffffed10061b6271 R12: 0000000000000009
R13: 1ffff920006e4fb8 R14: ffffffffffffffff R15: 0000000000000000
 __do_sys_perf_event_open kernel/events/core.c:12648 [inline]
 __se_sys_perf_event_open+0x505/0x1c20 kernel/events/core.c:12567
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9af4f8f749
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:00007f9af31f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f9af51e6180 RCX: 00007f9af4f8f749
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000140
RBP: 00007f9af5013f91 R08: 0000000000000002 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9af51e6218 R14: 00007f9af51e6180 R15: 00007ffc234b09b8
 </TASK>
CPU: 0 PID: 9422 Comm: syz.6.859 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:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215
Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 9c 92 c4 0c 48 89 de 5b e9 43 9d 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d f0 24 7e 7e 65 8b 15 f1 24 7e 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000006a70 EFLAGS: 00000297
RAX: ffffffff813aa819 RBX: ffffffff8e6263fc RCX: ffff888027465a00
RDX: 0000000000000100 RSI: ffffffff81e6251c RDI: ffffffff81e62507
RBP: ffffffff8e6263f4 R08: ffffc90000006c10 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8e6263f8
R13: ffffffff81e62507 R14: ffffffff81e6251c R15: ffffffff8e6263f4
FS:  00007f9af5d6d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33223ffc CR3: 000000005edef000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __orc_find arch/x86/kernel/unwind_orc.c:99 [inline]
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x4d9/0x2970 arch/x86/kernel/unwind_orc.c:494
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __set_page_owner+0x1d/0x60 mm/page_owner.c:192
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3519
 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915
 packet_rcv+0x5dd/0x13d0 net/packet/af_packet.c:2218
 deliver_skb net/core/dev.c:2264 [inline]
 dev_queue_xmit_nit+0x5f6/0xbb0 net/core/dev.c:2334
 xmit_one net/core/dev.c:3615 [inline]
 dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3635
 sch_direct_xmit+0x252/0x4a0 net/sched/sch_generic.c:345
 __dev_xmit_skb net/core/dev.c:3856 [inline]
 __dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4391
 dev_queue_xmit include/linux/netdevice.h:3113 [inline]
 neigh_hh_output include/net/neighbour.h:527 [inline]
 neigh_output include/net/neighbour.h:541 [inline]
 ip6_finish_output2+0xdf5/0x1650 net/ipv6/ip6_output.c:141
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ndisc_send_skb+0xbed/0x14b0 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x2bc/0x600 net/ipv6/addrconf.c:4006
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:32 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:107 [inline]
RIP: 0010:lock_release+0x13b/0x8b0 kernel/locking/lockdep.c:5770
Code: 84 c0 0f 85 20 05 00 00 83 3b 00 0f 85 51 04 00 00 4c 89 74 24 10 48 c7 84 24 a0 00 00 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 <48> 8b 84 24 a0 00 00 00 48 89 44 24 50 fa 48 c7 c7 c0 c9 aa 8a e8
RSP: 0018:ffffc900030a7660 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880274664dc RCX: 00b9c80e35cc4900
RDX: 0000000000000000 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: ffffc900030a7780 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: ffffffff812ffefa
R13: dffffc0000000000 R14: ffff888027465a00 R15: 1ffff92000614ed8
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 __text_poke+0x8da/0xb20 arch/x86/kernel/alternative.c:2097
 text_poke arch/x86/kernel/alternative.c:2121 [inline]
 text_poke_bp_batch+0x243/0x930 arch/x86/kernel/alternative.c:2429
 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
 static_key_enable+0x1a/0x20 kernel/jump_label.c:220
 tracepoint_add_func+0x83b/0x9a0 kernel/tracepoint.c:361
 tracepoint_probe_register_prio kernel/tracepoint.c:511 [inline]
 tracepoint_probe_register+0x5e/0x90 kernel/tracepoint.c:531
 perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
 perf_trace_event_init+0x4d2/0x9b0 kernel/trace/trace_event_perf.c:202
 perf_trace_init+0x238/0x2d0 kernel/trace/trace_event_perf.c:226
 perf_tp_event_init+0x8d/0x110 kernel/events/core.c:10204
 perf_try_init_event+0x12b/0x3c0 kernel/events/core.c:11818
 perf_init_event kernel/events/core.c:11888 [inline]
 perf_event_alloc+0xfa4/0x21b0 kernel/events/core.c:12169
 __do_sys_perf_event_open kernel/events/core.c:12676 [inline]
 __se_sys_perf_event_open+0x70e/0x1c20 kernel/events/core.c:12567
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9af4f8f749
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:00007f9af5d6d038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f9af51e5fa0 RCX: 00007f9af4f8f749
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000200000000a80
RBP: 00007f9af5013f91 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9af51e6038 R14: 00007f9af51e5fa0 R15: 00007ffc234b09b8
 </TASK>