rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=cbec/0/0x1 softirq=9599/9599 fqs=0 (t=10500 jiffies g=10185 q=5 ncpus=2) rcu: rcu_preempt kthread starved for 10500 jiffies! g10185 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:26464 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4448 Comm: syz.0.27 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:lockdep_hardirqs_on+0x60/0x140 kernel/locking/lockdep.c:4365 Code: 75 4d 65 8b 05 91 0c f2 75 85 c0 75 77 65 8b 05 76 09 f2 75 85 c0 75 6c 83 3d 3b 84 8c 0c 00 75 2e 48 c7 04 24 00 00 00 00 9c <8f> 04 24 f7 04 24 00 02 00 00 75 66 83 3d 1d 84 8c 0c 00 75 10 48 RSP: 0018:ffffc90003477b00 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88801be65940 RCX: c9d150d6e7d96400 RDX: dffffc0000000000 RSI: ffffffff8a6c1780 RDI: ffffffff8a1a7e0f RBP: ffffc90003477c90 R08: dffffc0000000000 R09: ffffed1005d29129 R10: ffffed1005d29129 R11: 1ffff11005d29128 R12: dffffc0000000000 R13: 0000000000010000 R14: 0000000000000000 R15: 0000000000000010 FS: 00007f086a8d06c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000080 CR3: 00000000273ea000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] _raw_spin_unlock_irq+0x1f/0x40 kernel/locking/spinlock.c:202 set_current_blocked kernel/signal.c:3044 [inline] signal_delivered kernel/signal.c:2907 [inline] signal_setup_done+0x28c/0x440 kernel/signal.c:2919 handle_signal arch/x86/kernel/signal.c:846 [inline] arch_do_signal_or_restart+0xecc/0x1240 arch/x86/kernel/signal.c:873 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f086984d6e0 Code: 44 24 20 0f 29 44 24 30 0f 29 44 24 40 48 8b 44 24 08 ff d0 48 83 c4 50 31 c0 5b 5d 41 5c 41 5d 41 5e c3 0f 1f 80 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 c3 66 66 2e 0f 1f RSP: 002b:00007f086a8cfa38 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007ffe1845d0b0 RCX: 0000000000000001 RDX: 00007f086a8cfa40 RSI: 00007f086a8cfb70 RDI: 0000000000000011 RBP: 00007f086a8d0040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010 R13: 00007f0869be6038 R14: 00007ffe1845d080 R15: 000000000000549e CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742 Code: 48 89 df e8 a7 b3 b6 f7 e9 4c ff ff ff e8 9d 0e f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d c7 40 4c 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffc90000177de8 EFLAGS: 000002c6 RAX: 20d1342147043700 RBX: ffffffff8a1a6267 RCX: 20d1342147043700 RDX: 0000000000000001 RSI: ffffffff8a6c0600 RDI: ffffffff8abef920 RBP: ffffc90000177f20 R08: dffffc0000000000 R09: ffffed10171e6afa R10: ffffed10171e6afa R11: 1ffff110171e6af9 R12: 0000000000000001 R13: dffffc0000000000 R14: ffff88813fef1dc0 R15: 1ffffffff1bfe206 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c008300000 CR3: 00000000273ea000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1fc/0x570 kernel/sched/idle.c:303 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401 start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281 secondary_startup_64_no_verify+0xcf/0xdb