rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21903/1:b..l rcu: (detected by 0, t=10502 jiffies, g=162861, q=298 ncpus=2) task:syz.1.4307 state:R running task stack:26984 pid:21903 ppid:13936 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:pid_nr_ns kernel/pid.c:-1 [inline] RIP: 0010:__task_pid_nr_ns+0x2d9/0x470 kernel/pid.c:503 Code: 89 c5 31 ff 89 c6 e8 26 be 2d 00 85 ed 0f 84 df 00 00 00 80 3d eb 76 1c 0d 01 0f 85 dc 00 00 00 e8 5c ba 2d 00 e9 35 ff ff ff <4e> 8d b4 3b d0 00 00 00 e8 4a ba 2d 00 4c 89 f0 48 c1 e8 03 42 0f RSP: 0018:ffffc900032f7ed8 EFLAGS: 00000246 RAX: 1ffff1100f0d94e5 RBX: ffff8880786ca640 RCX: 0000000000000002 RDX: ffff888023dc1e00 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2239aa0 R10: dffffc0000000000 R11: fffffbfff2239aa1 R12: ffff8880786ca728 R13: dffffc0000000000 R14: ffff888064215330 R15: 0000000000000010 task_tgid_vnr include/linux/sched.h:1649 [inline] __ia32_sys_getpid+0x1d/0x20 kernel/sys.c:960 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: 0033:0x7f7c8eb96bd7 RSP: 002b:00007f7c8cdf5b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: ffffffffffffffda RBX: 00007f7c8cdf5c70 RCX: 00007f7c8eb96bd7 RDX: 00007f7c8cdf5b40 RSI: 00007f7c8cdf5c70 RDI: 0000000000000021 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f7c8ee16038 R14: 00007ffd106ea340 R15: 00007ffd106ea428 rcu: rcu_preempt kthread starved for 10494 jiffies! g162861 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:26568 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212 Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 0c 3d 04 0d 48 89 de 5b e9 c3 70 57 00 cc cc cc 0f 1e fa 48 8b 04 24 65 48 8b 0d a0 8a 7c 7e 65 8b 15 a1 8a 7c RSP: 0018:ffffc900001f03d0 EFLAGS: 00000202 RAX: ffffffff8eee3da4 RBX: ffffffff8eee3da8 RCX: ffff88801c263c00 RDX: 0000000000000100 RSI: ffffffff8874a042 RDI: ffffffff88749f52 RBP: ffffffff8eee3da8 R08: ffffc900001f0570 R09: 0000000000000004 R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8eee3dac R13: ffffffff88749f52 R14: ffffffff8874a042 R15: ffffffff8eee3da8 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc76765075a CR3: 000000007da5b000 CR4: 00000000003506e0 Call Trace: __orc_find arch/x86/kernel/unwind_orc.c:99 [inline] orc_find arch/x86/kernel/unwind_orc.c:227 [inline] unwind_next_frame+0x501/0x2970 arch/x86/kernel/unwind_orc.c:494 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_slab_alloc+0x6c/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] kmem_cache_alloc_node+0x14c/0x320 mm/slub.c:3540 __alloc_skb+0x103/0x2c0 net/core/skbuff.c:643 __netdev_alloc_skb+0x10c/0x500 net/core/skbuff.c:717 netdev_alloc_skb include/linux/skbuff.h:3304 [inline] dev_alloc_skb include/linux/skbuff.h:3317 [inline] __ieee80211_beacon_get+0xe17/0x1600 net/mac80211/tx.c:5449 ieee80211_beacon_get_tim+0xbf/0x580 net/mac80211/tx.c:5571 ieee80211_beacon_get include/net/mac80211.h:5440 [inline] mac80211_hwsim_beacon_tx+0x3c7/0x780 drivers/net/wireless/virtual/mac80211_hwsim.c:2265 __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:1754 [inline] __hrtimer_run_queues+0x520/0xc40 kernel/time/hrtimer.c:1818 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1835 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: 88 1f 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 43 e4 3f 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:ffffc90000187de0 EFLAGS: 000002c2 RAX: 8120e0c521320c00 RBX: ffffffff8162ae21 RCX: 8120e0c521320c00 RDX: 0000000000000001 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9c20 RBP: ffffc90000187f20 R08: ffff8880b8f36bab R09: 1ffff110171e6d75 R10: dffffc0000000000 R11: ffffed10171e6d76 R12: 1ffff92000030fc8 R13: dffffc0000000000 R14: 1ffff1100384c780 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+0x221/0x590 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b