rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (21187 ticks this GP) idle=ec3/1/0x4000000000000000 softirq=7340/7343 fqs=0 (t=10502 jiffies g=8049 q=198) rcu: rcu_preempt kthread starved for 10503 jiffies! g8049 f0x0 RCU_GP_INIT(4) ->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:27968 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6552 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6577 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202 rcu_gp_init+0xcea/0x10e0 kernel/rcu/tree.c:1869 rcu_gp_kthread+0x164/0x350 kernel/rcu/tree.c:2135 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: 4629 Comm: syz.3.103 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:stack_trace_consume_entry+0x7/0x270 kernel/stacktrace.c:83 Code: 00 48 3b 4c 24 78 75 09 48 8d 65 f0 5b 41 5e 5d c3 e8 bd b8 41 08 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 41 57 41 56 41 55 <41> 54 53 48 83 ec 18 48 ba 00 00 00 00 00 fc ff df 4c 8d 47 10 4c RSP: 0018:ffffc9000344f680 EFLAGS: 00000086 RAX: ffffffff81662641 RBX: ffffc9000344f760 RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff81662641 RDI: ffffc9000344f760 RBP: ffffc9000344f730 R08: dffffc0000000000 R09: ffffc9000344f6f8 R10: fffff52000689ee1 R11: 1ffff92000689edf R12: ffff88802b559dc0 R13: ffff888080edb690 R14: ffffffff816674c0 R15: ffffc9000344f6a8 FS: 00007f5acc21a6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5ace5fb098 CR3: 000000002bdda000 CR4: 00000000003506e0 DR0: 000000000000fffe DR1: 0000000000000003 DR2: 0000000000000e8f DR3: 0000000000000007 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x100/0x140 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kmem_cache_free+0x8f/0x210 mm/slub.c:3515 __sigqueue_free kernel/signal.c:458 [inline] collect_signal kernel/signal.c:597 [inline] __dequeue_signal+0x4c4/0x5d0 kernel/signal.c:619 dequeue_signal+0xa2/0x440 kernel/signal.c:639 get_signal+0x6fe/0x12c0 kernel/signal.c:2781 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: 0033:0x7f5ace3d3be9 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:00007f5acc21a0e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007f5ace5fb098 RCX: 00007f5ace3d3be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5ace5fb098 RBP: 00007f5ace5fb090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5ace5fb128 R14: 00007fffedf0a3c0 R15: 00007fffedf0a4a8 NMI backtrace for cpu 0 CPU: 0 PID: 4628 Comm: syz.3.103 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x6d8/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 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_rq_unlock_irq+0x13/0x90 kernel/sched/sched.h:1339 Code: c0 48 8b 3c 24 e8 fd b4 68 00 eb b5 66 2e 0f 1f 84 00 00 00 00 00 90 41 57 41 56 53 eb 11 e8 d4 27 5e 08 e8 bf 6f 2a 00 fb 5b <41> 5e 41 5f c3 49 be 00 00 00 00 00 fc ff df 49 89 ff 48 8d 9f 58 RSP: 0018:ffffc90003407848 EFLAGS: 00000286 RAX: 68cfbde320e70400 RBX: ffff8880b903a300 RCX: 68cfbde320e70400 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc90003407a40 R08: dffffc0000000000 R09: ffffed1017207461 R10: ffffed1017207461 R11: 1ffff11017207460 R12: 1ffff110172075a3 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff8880b903b048 __schedule+0x1461/0x43b0 kernel/sched/core.c:6382 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x22d/0x440 kernel/futex/core.c:2863 futex_wait+0x202/0x5c0 kernel/futex/core.c:2964 do_futex+0xd1c/0x1240 kernel/futex/core.c:3982 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f5ace3d3be9 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:00007f5acc23b0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f5ace5fafa8 RCX: 00007f5ace3d3be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5ace5fafa8 RBP: 00007f5ace5fafa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5ace5fb038 R14: 00007fffedf0a3c0 R15: 00007fffedf0a4a8 sched: RT throttling activated