rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=7949, q=120) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294978702-4294968200), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g7949 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:25688 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 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: NMI backtrace for cpu 0 CPU: 0 PID: 4372 Comm: syz.3.18 Not tainted 5.15.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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:lockdep_enabled kernel/locking/lockdep.c:88 [inline] RIP: 0010:lock_is_held_type+0x35/0x180 kernel/locking/lockdep.c:5659 Code: 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 bd ff ff ff ff 83 3d fc ea cb 03 00 0f 84 00 01 00 00 65 8b 05 9b d7 c3 75 <85> c0 0f 85 f1 00 00 00 65 4c 8b 2d 4b ce c3 75 41 83 bd ec 0a 00 RSP: 0018:ffffc90003d0f8f8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88807ec4d940 RCX: ffff88807ec4d940 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb1fbe0 RBP: 00000000ffffffff R08: ffffffff81b9d44c R09: ffffc90003d0fbb0 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: 00007ffd9e760b00 R14: dffffc0000000000 R15: 1ffff920007a1f30 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0xf1/0x6a0 kernel/sched/core.c:9602 __might_fault+0x6b/0x110 mm/memory.c:5352 __copy_from_user include/linux/uaccess.h:109 [inline] check_xstate_in_sigframe arch/x86/kernel/fpu/signal.c:33 [inline] __fpu_restore_sig arch/x86/kernel/fpu/signal.c:317 [inline] fpu__restore_sig+0x1db/0x1100 arch/x86/kernel/fpu/signal.c:466 restore_sigcontext+0x638/0x710 arch/x86/kernel/signal.c:139 __do_sys_rt_sigreturn+0x190/0x250 arch/x86/kernel/signal.c:674 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f67ef0d3809 Code: 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 01 48 RSP: 002b:00007ffd9e760ec8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f67ef298fa0 RCX: 00007f67ef0d3809 RDX: 000000002006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f67ef14693e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f67ef298fa0 R14: 00007f67ef298fa0 R15: 0000000000001418