rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10454 ticks this GP) idle=63ec/1/0x4000000000000000 softirq=15913/15916 fqs=4859 rcu: hardirqs softirqs csw/system rcu: number: 1309471 6 0 rcu: cputime: 15865 36614 48 ==> 52510(ms) rcu: (t=10504 jiffies g=16141 q=2058 ncpus=2) rcu: rcu_preempt kthread timer wakeup didn't happen for 386 jiffies! g16141 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=19286 rcu: rcu_preempt kthread starved for 389 jiffies! g16141 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:26984 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 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 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: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 4e 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 03 19 42 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffc900000076f8 EFLAGS: 00000246 RAX: ffffffff813aa578 RBX: 0000000000000003 RCX: ffffffff8ce93440 RDX: 0000000000000100 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8de0 RBP: ffffc900000077d0 R08: ffffffff911c456f R09: 1ffffffff22388ad R10: dffffc0000000000 R11: fffffbfff22388ae R12: dffffc0000000000 R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000000ee4 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d6ddaf8a38 CR3: 000000000cf32000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] kvm_wait+0x23d/0x2a0 arch/x86/kernel/kvm.c:1058 pv_wait arch/x86/include/asm/paravirt.h:598 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x61a/0x9d0 kernel/locking/qspinlock.c:511 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x23e/0x2c0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:351 [inline] mac80211_hwsim_tx_frame_no_nl+0x735/0x11a0 drivers/net/wireless/virtual/mac80211_hwsim.c:1791 mac80211_hwsim_tx_frame+0x1b5/0x200 drivers/net/wireless/virtual/mac80211_hwsim.c:2176 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+0x520/0xc40 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:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 4e 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 03 19 42 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c2 RAX: 81a113e9a88fdc00 RBX: ffffffff8162a9dd RCX: 81a113e9a88fdc00 RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8de0 RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65 R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19c0fbc R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:178 [inline] do_idle+0x33d/0x590 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b CPU: 1 PID: 7013 Comm: syz.2.306 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__nr_to_section include/linux/mmzone.h:1849 [inline] RIP: 0010:__pfn_to_section include/linux/mmzone.h:1957 [inline] RIP: 0010:lookup_page_ext mm/page_ext.c:237 [inline] RIP: 0010:page_ext_get+0x137/0x2b0 mm/page_ext.c:509 Code: 32 97 e8 0c 1f f5 ff 48 8b 05 f5 1e 48 15 48 85 c0 74 42 4c 89 f1 48 c1 e9 16 4c 8d 3c c8 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 ff e8 df 1e f5 ff 4d 8b 3f 4d 85 ff 74 20 4d 89 f5 49 RSP: 0018:ffffc900001ef6c0 EFLAGS: 00000246 RAX: 1ffff11047ffde00 RBX: ffffffff81ea38b2 RCX: 0000000000000000 RDX: 0000000000000100 RSI: 000000000007982d RDI: 00000003ffffffff RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff22388a0 R10: dffffc0000000000 R11: fffffbfff22388a1 R12: dffffc0000000000 R13: ffffc900001ef908 R14: 000000000007982d R15: ffff88823ffef000 FS: 00007f904acba6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555812ff4e8 CR3: 000000007d029000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __page_table_check_zero+0x138/0x4b0 mm/page_table_check.c:148 prep_new_page mm/page_alloc.c:1588 [inline] get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500 alloc_slab_page+0x5d/0x160 mm/slub.c:1881 allocate_slab mm/slub.c:2028 [inline] new_slab+0x87/0x2d0 mm/slub.c:2081 ___slab_alloc+0xc5d/0x12f0 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] kmem_cache_alloc_node+0x1e6/0x320 mm/slub.c:3540 __alloc_skb+0x103/0x2c0 net/core/skbuff.c:643 skb_copy+0x13d/0x7a0 net/core/skbuff.c:1987 mac80211_hwsim_tx_frame_no_nl+0xca9/0x11a0 drivers/net/wireless/virtual/mac80211_hwsim.c:1840 mac80211_hwsim_tx+0x1808/0x2720 drivers/net/wireless/virtual/mac80211_hwsim.c:2058 drv_tx net/mac80211/driver-ops.h:37 [inline] wake_tx_push_queue net/mac80211/util.c:305 [inline] ieee80211_handle_wake_tx_queue+0x199/0x2b0 net/mac80211/util.c:322 drv_wake_tx_queue net/mac80211/driver-ops.h:1251 [inline] schedule_and_wake_txq net/mac80211/driver-ops.h:1258 [inline] ieee80211_queue_skb+0x1a3e/0x21c0 net/mac80211/tx.c:1678 ieee80211_tx+0x2c3/0x460 net/mac80211/tx.c:1980 __ieee80211_subif_start_xmit+0xe10/0x1500 net/mac80211/tx.c:4333 ieee80211_subif_start_xmit+0xf4/0x560 net/mac80211/tx.c:4527 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3632 [inline] dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3648 __dev_queue_xmit+0x19a3/0x3660 net/core/dev.c:4442 neigh_output include/net/neighbour.h:543 [inline] ip6_finish_output2+0xe3d/0x1630 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+0xc26/0x14f0 net/ipv6/ndisc.c:513 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 b0 63 32 09 e8 9b 29 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:ffffc900035d7758 EFLAGS: 00000282 RAX: 45ccc5473d9ea000 RBX: 0000000000000000 RCX: 45ccc5473d9ea000 RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8de0 RBP: ffffc900035d77b0 R08: ffffffff911c45ff R09: 1ffffffff22388bf R10: dffffc0000000000 R11: fffffbfff22388c0 R12: ffff8880322b1e00 R13: dffffc0000000000 R14: ffff88801be60000 R15: ffff8880b8f3cac8 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+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9049d9c819 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:00007f904acba028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f904a015fa0 RCX: 00007f9049d9c819 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480 RBP: 00007f9049e32c91 R08: 000000000000000a R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f904a016038 R14: 00007f904a015fa0 R15: 00007fff92f75ef8