rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=6917, q=32 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10498 (4294966968-4294956470), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10499 jiffies! g6917 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:28752 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6745 __schedule_loop kernel/sched/core.c:6822 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6837 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2000 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2202 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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: 5131 Comm: syz-executor272 Not tainted 6.9.0-syzkaller-09429-g61307b7be41a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:lock_acquire+0xe/0x560 kernel/locking/lockdep.c:5722 Code: ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 b8 00 00 00 00 00 fc ff df <41> 57 4d 89 cf 41 56 49 89 fe 41 55 41 89 d5 41 54 45 89 c4 55 53 RSP: 0018:ffffc90000007d10 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff888023b66540 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8dbb1760 RBP: ffff8880292c28c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: 1ffff92000000faa R15: ffff888079754070 FS: 000055555b1a53c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002006b000 CR3: 0000000079752000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] rcu_read_lock include/linux/rcupdate.h:781 [inline] send_sigqueue+0x112/0x850 kernel/signal.c:1979 posix_timer_event kernel/time/posix-timers.c:298 [inline] posix_timer_fn+0x181/0x3e0 kernel/time/posix-timers.c:324 __run_hrtimer kernel/time/hrtimer.c:1687 [inline] __hrtimer_run_queues+0x20c/0xcc0 kernel/time/hrtimer.c:1751 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1813 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x10f/0x450 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 7a 10 82 f6 48 89 df e8 62 8d 82 f6 e8 cd 79 ab f6 fb bf 01 00 00 00 e2 cd 73 f6 65 8b 05 73 1b 1a 75 85 c0 74 06 5b c3 cc cc cc cc RSP: 0018:ffffc900031c7cf0 EFLAGS: 00000206 RAX: 00000000039dad7d RBX: ffff88802f234a00 RCX: 1ffffffff1fc7951 RDX: 0000000000000000 RSI: ffffffff8b2cab60 RDI: 0000000000000001 RBP: ffff88802f234e00 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8fe40d17 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000021 R14: ffff88802f234a00 R15: ffff88802f234a00 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1e3e/0x2710 kernel/signal.c:2914 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f77e737de79 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff29e799c8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f77e737de79 RDX: 000000002006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000055555b1a5370 R13: 0000000000000003 R14: 00007fff29e79a40 R15: 00007fff29e79a30 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.801 msecs