rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 GPs behind) idle=19d4/1/0x4000000000000000 softirq=69920/69921 fqs=5243 rcu: hardirqs softirqs csw/system rcu: number: 7745335 0 0 rcu: cputime: 25125 27402 0 ==> 52510(ms) rcu: (detected by 0, t=10502 jiffies, g=92009, q=878 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17729 Comm: syz.0.3749 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:perf_prepare_sample+0x5/0x1df0 kernel/events/core.c:7753 Code: eb a5 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ac fe ff ff 4c 89 e7 e8 4a 31 31 00 e9 9f fe ff ff 0f 1f 44 00 00 f3 0f 1e fa 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 00 RSP: 0018:ffffc900001efe90 EFLAGS: 00000046 RAX: ffffffff81ae31f0 RBX: ffffc900001f0180 RCX: ffff88807e5f8000 RDX: ffff8880b8f36888 RSI: ffff88805a75aaa8 RDI: ffffc900001f0180 RBP: ffffc900001effa8 R08: dffffc0000000000 R09: 1ffffffff2237ea0 R10: dffffc0000000000 R11: fffffbfff2237ea1 R12: dffffc0000000000 R13: ffff88805a75aaa8 R14: ffff8880b8f36888 R15: 1ffff9200003dfd8 FS: 00007fdfa68346c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001e000 CR3: 000000005720b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __perf_event_output kernel/events/core.c:7972 [inline] perf_event_output_forward+0x187/0x3e0 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+0x324/0x630 kernel/events/core.c:-1 perf_tp_event+0x54f/0x1450 kernel/events/core.c:10344 perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10268 perf_trace_preemptirq_template+0x269/0x330 include/trace/events/preemptirq.h:14 trace_irq_enable+0xbb/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:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline] 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+0x4a3/0x2970 arch/x86/kernel/unwind_orc.c:494 Code: 74 24 48 48 89 d8 4c 29 e0 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 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 e8 db 4b 00 49 RSP: 0018:ffffc900001f0598 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: ffffffff8f063aa0 RCX: 0000000000000020 RDX: dffffc0000000000 RSI: 00000000001bb9c9 RDI: 00000000001bb9ea RBP: ffffffff8f063a20 R08: ffffc900001f0730 R09: 0000000000000011 R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8f063a20 R13: 00000000001bb9c9 R14: ffffffff8aa01449 R15: ffffffff8f063a60 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] kmem_cache_free+0xf8/0x270 mm/slub.c:3852 skb_kfree_head net/core/skbuff.c:947 [inline] skb_free_head net/core/skbuff.c:961 [inline] skb_release_data+0x60a/0x800 net/core/skbuff.c:991 skb_release_all net/core/skbuff.c:1057 [inline] __kfree_skb net/core/skbuff.c:1071 [inline] consume_skb+0xb2/0x110 net/core/skbuff.c:1287 mac80211_hwsim_beacon_tx+0x3e9/0x780 drivers/net/wireless/virtual/mac80211_hwsim.c:2269 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:766 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:802 mac80211_hwsim_beacon+0xbb/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2295 __run_hrtimer kernel/time/hrtimer.c:1750 [inline] __hrtimer_run_queues+0x52a/0xc40 kernel/time/hrtimer.c:1814 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1831 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:internal_get_user_pages_fast+0x2080/0x2760 mm/gup.c:3205 Code: e8 05 de be ff e9 4a ff ff ff e8 fb dd be ff e8 c6 15 bc 08 48 83 bc 24 b8 00 00 00 00 74 b0 e8 e6 dd be ff fb 83 7c 24 74 00 <48> 8b 4c 24 60 75 0a e8 d4 dd be ff e9 85 00 00 00 48 b8 00 00 00 RSP: 0018:ffffc9000b5aee40 EFLAGS: 00000246 RAX: ffffffff81c836ca RBX: 0000000000000000 RCX: 0000000000080000 RDX: ffffc9000fc11000 RSI: 000000000001fa67 RDI: 000000000001fa68 RBP: ffffc9000b5af050 R08: ffffffff911bf607 R09: 1ffffffff2237ec0 R10: dffffc0000000000 R11: fffffbfff2237ec1 R12: 0000000000000000 R13: 0200000000000000 R14: 000020000001f000 R15: 0000000000000000 get_user_page_fast_only include/linux/mm.h:2610 [inline] perf_virt_to_phys kernel/events/core.c:7619 [inline] perf_prepare_sample+0x10fc/0x1df0 kernel/events/core.c:7883 __perf_event_output kernel/events/core.c:7972 [inline] perf_event_output_forward+0x187/0x3e0 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+0x324/0x630 kernel/events/core.c:-1 do_perf_sw_event kernel/events/core.c:9935 [inline] ___perf_sw_event+0x4a7/0x730 kernel/events/core.c:9966 __perf_sw_event+0x139/0x270 kernel/events/core.c:9978 perf_sw_event include/linux/perf_event.h:1442 [inline] do_user_addr_fault+0x123e/0x12c0 arch/x86/mm/fault.c:1278 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:71 Code: 75 f1 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 a4 c3 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 29 f8 48 01 RSP: 0018:ffffc9000b5af818 EFLAGS: 00050206 RAX: ffffffff84272301 RBX: 0000000000008000 RCX: 0000000000002140 RDX: 0000000000000001 RSI: 000020000001e000 RDI: ffff888065af5ec0 RBP: ffffc9000b5af970 R08: ffff888065af7fff R09: 1ffff1100cb5efff R10: dffffc0000000000 R11: ffffed100cb5f000 R12: ffff888065af0000 R13: 0000200000018140 R14: ffffc9000b5afc18 R15: 1ffff920016b5f83 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:127 [inline] copyin lib/iov_iter.c:193 [inline] _copy_from_iter+0x24e/0x12e0 lib/iov_iter.c:390 copy_from_iter include/linux/uio.h:209 [inline] copy_from_iter_full include/linux/uio.h:216 [inline] skb_do_copy_data_nocache include/net/sock.h:2342 [inline] skb_copy_to_page_nocache include/net/sock.h:2368 [inline] kcm_sendmsg+0xd95/0x28b0 net/kcm/kcmsock.c:858 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x2df/0x420 net/socket.c:1160 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x46c/0x990 fs/read_write.c:584 ksys_write+0x150/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdfa599af79 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:00007fdfa6834028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fdfa5c15fa0 RCX: 00007fdfa599af79 RDX: 00000000fffffdef RSI: 0000200000000140 RDI: 000000000000000b RBP: 00007fdfa5a316e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdfa5c16038 R14: 00007fdfa5c15fa0 R15: 00007fff40043628