rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=186c/1/0x4000000000000002 softirq=15978/15979 fqs=1 (detected by 0, t=10504 jiffies, g=20141, q=39 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5994 Comm: syz.3.399 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:137 [inline] RIP: 0010:class_irqsave_destructor include/linux/irqflags.h:274 [inline] RIP: 0010:perf_swevent_event+0x4b5/0x570 kernel/events/core.c:9651 Code: 42 c6 44 33 04 f8 4c 89 fe 48 81 e6 00 02 00 00 31 ff e8 fe a9 dc ff 49 81 e7 00 02 00 00 75 11 e8 10 a6 dc ff 4d 85 e4 75 16 06 a6 dc ff eb 15 e8 ff a5 dc ff e8 ca 38 8e 08 4d 85 e4 74 ea RSP: 0018:ffffc900001e0560 EFLAGS: 00000046 RAX: ffffffff81a5a070 RBX: 1ffff9200003c0b0 RCX: ffff888076613c00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900001e0630 R08: ffffffff8f00d22f R09: 1ffffffff1e01a45 R10: dffffc0000000000 R11: fffffbfff1e01a46 R12: 0000000000000000 R13: 0000000000000009 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f89425a06c0(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff0cf511990 CR3: 000000003055b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: perf_tp_event+0x36b/0xc10 kernel/events/core.c:10074 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10042 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 68 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc900001e0ae0 EFLAGS: 00000206 RAX: 4e77f2df182d6d00 RBX: 1ffff9200003c164 RCX: 4e77f2df182d6d00 RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: ffffffff8adf71a0 RBP: ffffc900001e0bd0 R08: ffffffff9193424f R09: 1ffffffff2326849 R10: dffffc0000000000 R11: fffffbfff232684a R12: 0000000000000246 R13: dffffc0000000000 R14: ffff8880b8d3bb00 R15: 0000000000000002 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:823 [inline] ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2153 __run_hrtimer kernel/time/hrtimer.c:1751 [inline] __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815 hrtimer_run_softirq+0x173/0x290 kernel/time/hrtimer.c:1832 handle_softirqs+0x291/0x910 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:fsnotify_inode_watches_children include/linux/fsnotify_backend.h:566 [inline] RIP: 0010:fsnotify_update_flags include/linux/fsnotify_backend.h:591 [inline] RIP: 0010:__d_instantiate+0x3c5/0x700 fs/dcache.c:2020 Code: 74 08 4c 89 e7 e8 db d0 eb ff 41 be 6c 04 00 00 4d 03 34 24 4c 89 f0 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28 <84> c0 0f 85 3a 02 00 00 41 8b 2e 89 ee 81 e6 00 00 00 08 41 0f 94 RSP: 0018:ffffc90003367c10 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: ffff8880551c0758 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffff8880551c07eb R09: 1ffff1100aa380fd R10: dffffc0000000000 R11: ffffed100aa380fe R12: ffff8880551c07c0 R13: dffffc0000000000 R14: ffff888018857c1c R15: 1ffff1100aa380eb d_instantiate+0x6b/0x90 fs/dcache.c:2045 alloc_file_pseudo+0x16f/0x200 fs/file_table.c:271 __anon_inode_getfile fs/anon_inodes.c:122 [inline] anon_inode_getfile+0xc1/0x1a0 fs/anon_inodes.c:160 __do_sys_perf_event_open kernel/events/core.c:12654 [inline] __se_sys_perf_event_open+0xc2a/0x1ec0 kernel/events/core.c:12428 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f894179e1d9 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:00007f89425a0028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f8941a26090 RCX: 00007f894179e1d9 RDX: fffffffdffffffff RSI: 0000000000000000 RDI: 0000200000000600 RBP: 00007f8941835888 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8941a26128 R14: 00007f8941a26090 R15: 00007ffcdea27568 rcu: rcu_preempt kthread starved for 10502 jiffies! g20141 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28016 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 5976 Comm: syz.0.395 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:1064 Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 c7 2b 50 00 44 38 e3 75 10 66 90 0f 00 2d a9 f5 50 09 fb f4 16 ff ff ff fb e9 10 ff ff ff e8 77 55 fb 08 89 f9 80 e1 07 38 RSP: 0000:ffffc900033a7760 EFLAGS: 00000246 RAX: fce860e2ada3dc00 RBX: 0000000000000003 RCX: fce860e2ada3dc00 RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: ffffffff8adf71a0 RBP: ffffc900033a7810 R08: ffffffff9193427f R09: 1ffffffff232684f R10: dffffc0000000000 R11: fffffbfff2326850 R12: 0000000000000003 R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff92000674eec FS: 00007ff0cf4f06c0(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f41faa27dac CR3: 00000000313b9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:603 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:511 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:351 [inline] dentry_kill+0xe6/0x290 fs/dcache.c:742 dput+0xfa/0x1d0 fs/dcache.c:918 __fput+0x597/0x8b0 fs/file_table.c:328 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x118d/0x1340 kernel/signal.c:2661 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:295 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff0ce59e1d9 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:00007ff0cf4effd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffffc RBX: 00007ff0ce826180 RCX: 00007ff0ce59e1d9 RDX: 0000200000001c40 RSI: 0000200000001c30 RDI: 0000000000201000 RBP: 00007ff0ce635888 R08: 0000200000001cc0 R09: 0000200000001cc0 R10: 0000200000001c80 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ff0ce826218 R14: 00007ff0ce826180 R15: 00007ffe7a280a98