rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=8037, q=156) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294959214-4294948711), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g8037 f0x2 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:28176 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 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: 4377 Comm: syz.1.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:rcu_rnp_online_cpus kernel/rcu/tree.c:222 [inline] RIP: 0010:rcu_lockdep_current_cpu_online+0xbd/0x130 kernel/rcu/tree.c:1173 Code: 20 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 e6 6b 59 00 4d 8b 26 4c 8d 73 70 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 c9 6b 59 00 4d 85 26 75 27 48 83 c3 78 48 89 d8 RSP: 0018:ffffc90000dd0c08 EFLAGS: 00000046 RAX: 1ffffffff1864706 RBX: ffffffff8c3237c0 RCX: cc3d295f5f70bb00 RDX: 0000000000010000 RSI: ffffffff8a7a09a0 RDI: ffff8880b913b1d8 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203b018 R10: dffffc0000000000 R11: fffffbfff203b019 R12: 0000000000000002 R13: ffff88807cef26e8 R14: ffffffff8c323830 R15: dffffc0000000000 FS: 0000555576886500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 0000000075a72000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held+0x1a/0x40 kernel/rcu/update.c:309 __lock_task_sighand+0xf3/0x290 kernel/signal.c:1389 lock_task_sighand include/linux/sched/signal.h:710 [inline] send_sigqueue+0x177/0x620 kernel/signal.c:1975 posix_timer_event kernel/time/posix-timers.c:360 [inline] posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae bd 96 f7 48 89 df e8 e6 95 97 f7 e8 81 8b b8 f7 fb bf 01 00 00 00 c6 9c 8b f7 65 8b 05 e7 85 3b 76 85 c0 74 02 5b c3 e8 34 93 39 RSP: 0018:ffffc900033afbc0 EFLAGS: 00000282 RAX: cc3d295f5f70bb00 RBX: ffff88805ba55c80 RCX: cc3d295f5f70bb00 RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffff88805ba55c83 R09: 1ffff1100b74ab90 R10: dffffc0000000000 R11: ffffed100b74ab91 R12: ffff88805ba55c80 R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004 spin_unlock_irq include/linux/spinlock.h:414 [inline] get_signal+0x11e2/0x12d0 kernel/signal.c:2903 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ff4d1a18e59 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:00007ffcd65b77f8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007ff4d1c91fa0 RCX: 00007ff4d1a18e59 RDX: 0000200000000040 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 00007ff4d1aaed6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff4d1c91fac R14: 00007ff4d1c91fa0 R15: 00007ff4d1c91fa0 sched: RT throttling activated