rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10500 ticks this GP) idle=6654/1/0x4000000000000000 softirq=18143/18144 fqs=4325 rcu: hardirqs softirqs csw/system rcu: number: 1520654 0 0 rcu: cputime: 15708 36791 36 ==> 52520(ms) rcu: (t=10503 jiffies g=20425 q=3431 ncpus=2) CPU: 0 PID: 7407 Comm: syz.1.522 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x2e/0x90 kernel/kcov.c:313 Code: 48 8b 04 24 65 48 8b 15 f0 86 7c 7e 65 8b 0d f1 86 7c 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba 1c 16 00 00 00 <74> 52 8b 8a f8 15 00 00 83 f9 03 75 47 48 8b 8a 00 16 00 00 44 8b RSP: 0018:ffffc900000074b0 EFLAGS: 00000246 RAX: ffffffff813b385f RBX: 1ffff92000000eb1 RCX: 0000000000000100 RDX: ffff88802ac81e00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffc90000007650 R09: 000000000000000e R10: 0000000000000004 R11: 0000000000000100 R12: ffffc90000007588 R13: dffffc0000000000 R14: ffffc900000075c0 R15: ffffffff815d6faa FS: 00007f676f1246c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7979462b7a CR3: 00000000245e1000 CR4: 00000000003506f0 Call Trace: unwind_done arch/x86/include/asm/unwind.h:50 [inline] unwind_next_frame+0x9f/0x2970 arch/x86/kernel/unwind_orc.c:475 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 __kfence_alloc+0x2d7/0x3d0 mm/kfence/core.c:1133 kfence_alloc include/linux/kfence.h:129 [inline] slab_alloc_node mm/slub.c:3481 [inline] kmem_cache_alloc_node+0x2b4/0x320 mm/slub.c:3540 __alloc_skb+0x103/0x2c0 net/core/skbuff.c:643 alloc_skb include/linux/skbuff.h:1316 [inline] ndisc_alloc_skb+0xa6/0x450 net/ipv6/ndisc.c:423 ndisc_send_rs+0x2a6/0x610 net/ipv6/ndisc.c:707 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 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+0xd3/0x190 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255 Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 e0 94 34 09 e8 1b 2f 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90004327758 EFLAGS: 00000282 RAX: 67de27f3c5fb5f00 RBX: 0000000000000000 RCX: 67de27f3c5fb5f00 RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9c20 RBP: ffffc900043277b0 R08: ffffffff911cd5ff R09: 1ffffffff2239abf R10: dffffc0000000000 R11: fffffbfff2239ac0 R12: ffff88802ac81e00 R13: dffffc0000000000 R14: ffff888018e93c00 R15: ffff8880b8e3cb48 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x155b/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 smp_call_function_single+0x48d/0x5a0 kernel/smp.c:652 task_function_call kernel/events/core.c:120 [inline] perf_install_in_context+0x5be/0x920 kernel/events/core.c:2959 __do_sys_perf_event_open kernel/events/core.c:12957 [inline] __se_sys_perf_event_open+0x1836/0x1c50 kernel/events/core.c:12609 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f676e19ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f676f124028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f676e415fa0 RCX: 00007f676e19ce59 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 00002000000003c0 RBP: 00007f676e232d6f R08: 0000000000000003 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f676e416038 R14: 00007f676e415fa0 R15: 00007ffefd7f5c58