rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=87341, q=19) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295064841-4295054339), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g87341 f0x2 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:28032 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 20516 Comm: syz.5.4267 Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:127 [inline] RIP: 0010:lockdep_hardirqs_off+0x48/0x100 kernel/locking/lockdep.c:4370 Code: 90 00 00 00 48 89 fb 65 8b 05 7c 01 61 76 a9 00 00 f0 00 74 68 83 3d 06 b1 68 0c 00 75 15 48 c7 04 24 00 00 00 00 9c 8f 04 24 04 24 00 02 00 00 75 79 65 8b 05 b8 07 61 76 85 c0 74 56 65 4c RSP: 0018:ffffc9000381fac8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffffff89a1661a RCX: dbd5962386512600 RDX: 0000000000000000 RSI: ffffffff8a0b11e0 RDI: ffffffff8a59a740 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f9070ab66c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000004f0c2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: irqentry_enter+0x27/0x50 kernel/entry/common.c:-1 sysvec_apic_timer_interrupt+0xa/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: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 9a b1 f7 48 89 df e8 56 6f b2 f7 e8 a1 13 d3 f7 fb bf 01 00 00 00 86 93 a6 f7 65 8b 05 27 a3 57 76 85 c0 74 02 5b c3 e8 d4 ad 55 RSP: 0018:ffffc9000381fbc0 EFLAGS: 00000282 RAX: dbd5962386512600 RBX: ffff888067c75c80 RCX: dbd5962386512600 RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: 0000000000000001 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100cf8eb91 R10: ffffed100cf8eb91 R11: 1ffff1100cf8eb90 R12: ffff888067c75c80 R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x11d6/0x12c0 kernel/signal.c:2903 arch_do_signal_or_restart+0xc1/0x1300 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+0xb1/0x140 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: 0033:0x7f9072c4e927 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007f9070ab60e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f9072e75fa8 RCX: 00007f9072c4e929 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9072e75fa8 RBP: 00007f9072e75fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9072e75fac R13: 0000000000000000 R14: 00007fffed9aaaa0 R15: 00007fffed9aab88