rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (1 GPs behind) idle=7564/1/0x4000000000000000 softirq=25979/25981 fqs=2100 rcu: hardirqs softirqs csw/system rcu: number: 12023821 0 0 rcu: cputime: 6233 46283 0 ==> 52500(ms) rcu: (detected by 1, t=10505 jiffies, g=18593, q=226 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6758 Comm: syz-executor355 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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_cmp8+0x2e/0x80 kernel/kcov.c:320 Code: 48 8b 04 24 65 48 8b 0d 90 2a 7e 7e 65 8b 15 91 2a 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 1c 16 00 00 00 <74> 4e 8b 91 f8 15 00 00 83 fa 03 75 43 48 8b 91 00 16 00 00 44 8b RSP: 0018:ffffc90000006dd8 EFLAGS: 00000046 RAX: ffffffff81ac3d31 RBX: 0000000000000010 RCX: ffff88801e6cbc00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000006ed0 R08: dffffc0000000000 R09: 1ffffffff21b46a0 R10: dffffc0000000000 R11: fffffbfff21b46a1 R12: ffffc900000071c0 R13: dffffc0000000000 R14: 0000000000000500 R15: 0000000000000010 FS: 0000555572be3380(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000000014c CR3: 0000000018fb6000 CR4: 00000000003506f0 Call Trace: perf_prepare_sample+0x13a1/0x1c40 kernel/events/core.c:7907 __perf_event_output kernel/events/core.c:7971 [inline] perf_event_output_forward+0x152/0x3a0 kernel/events/core.c:7992 __perf_event_overflow+0x447/0x630 kernel/events/core.c:9717 perf_swevent_overflow kernel/events/core.c:9793 [inline] perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1 perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10343 perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10267 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:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900000075c0 EFLAGS: 00000206 RAX: 6b2189b8c1a9d800 RBX: 1ffff92000000ec0 RCX: 6b2189b8c1a9d800 RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc900000076a8 R08: ffffffff90da350f R09: 1ffffffff21b46a1 R10: dffffc0000000000 R11: fffffbfff21b46a2 R12: ffffffff8cd35400 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:818 [inline] is_bpf_text_address+0x27e/0x2a0 kernel/bpf/core.c:743 kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 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_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1806 [inline] slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] kmem_cache_free+0xf8/0x280 mm/slub.c:3838 rcu_do_batch kernel/rcu/tree.c:2194 [inline] rcu_core+0xcc4/0x1720 kernel/rcu/tree.c:2467 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x4b8/0x2970 arch/x86/kernel/unwind_orc.c:494 Code: 01 c8 48 83 e0 fe 4d 8d 3c 44 4c 89 f8 48 c1 e8 03 0f b6 04 10 84 c0 75 3e 4d 63 2f 4d 01 fd 4c 89 ef 4c 89 f6 e8 b8 e5 4a 00 <49> 8d 47 04 4d 39 f5 4c 0f 46 e0 49 8d 47 fc 48 0f 47 d8 49 0f 46 RSP: 0018:ffffc9000b947078 EFLAGS: 00000293 RAX: ffffffff813aa778 RBX: ffffffff8e624728 RCX: ffff88801e6cbc00 RDX: 0000000000000000 RSI: ffffffff81dbf44d RDI: ffffffff81dbf449 RBP: ffffffff8e624724 R08: ffffc9000b947210 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff8e624728 R13: ffffffff81dbf449 R14: ffffffff81dbf44d R15: ffffffff8e624728 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:3485 [inline] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509 kmem_cache_zalloc include/linux/slab.h:711 [inline] __proc_create+0x370/0x8d0 fs/proc/generic.c:425 proc_create_reg+0x8b/0x110 fs/proc/generic.c:552 proc_create_net_data+0x99/0x1b0 fs/proc/proc_net.c:120 ping_v6_proc_init_net+0x59/0x70 net/ipv6/ping.c:259 ops_init+0x397/0x640 net/core/net_namespace.c:139 setup_net+0x3a5/0xa00 net/core/net_namespace.c:343 copy_net_ns+0x36d/0x5e0 net/core/net_namespace.c:520 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110 copy_namespaces+0x430/0x4a0 kernel/nsproxy.c:179 copy_process+0x1700/0x3d70 kernel/fork.c:2509 kernel_clone+0x21b/0x840 kernel/fork.c:2914 __do_sys_clone kernel/fork.c:3057 [inline] __se_sys_clone kernel/fork.c:3041 [inline] __x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041 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: 0033:0x7f59721e7ab9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc26107018 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f59721e7ab9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000e50c1600 RBP: 0000000000032541 R08: 0000000000000000 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc2610702c R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 3.994 msecs