rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=fdd/1/0x4000000000000000 softirq=327880/327881 fqs=927 (t=10500 jiffies g=533289 q=26445) rcu: rcu_preempt kthread starved for 7849 jiffies! g533289 f0x0 RCU_GP_WAIT_FQS(5) ->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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4969 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6250 schedule+0xd2/0x260 kernel/sched/core.c:6323 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 1003 Comm: syz-executor.0 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__perf_event_overflow+0x18d/0x3d0 kernel/events/core.c:9209 Code: 00 00 48 85 ed 48 0f 44 eb e8 3f 3c e1 ff 48 b8 00 00 00 00 00 fc ff df 48 8d bd 20 04 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 05 02 00 00 48 83 bd 20 04 00 00 00 74 42 e8 0e 3c e1 ff 4c RSP: 0018:ffffc90000dc0bf8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff88802c8c5820 RCX: 0000000000000000 RDX: 1ffff11005918b88 RSI: ffffffff81968871 RDI: ffff88802c8c5c40 RBP: ffff88802c8c5820 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802c8c5c4c R13: ffffc90000dc0c80 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f91fca9d700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3062e000 CR3: 00000000b0762000 CR4: 0000000000350ee0 Call Trace: perf_swevent_hrtimer+0x37c/0x3f0 kernel/events/core.c:10597 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:rcu_lockdep_current_cpu_online+0xde/0x150 kernel/rcu/tree.c:1175 Code: 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 66 48 8b 45 70 48 85 c3 74 11 b8 01 00 00 00 65 ff 0d b4 25 9f 7e 74 2a <5b> 5d c3 48 8d 7d 78 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc900066278a0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffffff815cd891 RDX: 1ffffffff17318fe RSI: 0000000000000002 RDI: ffffffff8b98c7f0 RBP: ffffffff8b98c780 R08: 0000000000000000 R09: ffffffff8d6fc1d7 R10: fffffbfff1adf83a R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000400cc0 R14: 0000000000000020 R15: ffffffff81e32407 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held_common kernel/rcu/update.c:102 [inline] rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x522/0x720 kernel/locking/lockdep.c:5651 might_alloc include/linux/sched/mm.h:228 [inline] slab_pre_alloc_hook mm/slab.h:492 [inline] slab_alloc_node mm/slub.c:3148 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc_trace+0x42/0x2c0 mm/slub.c:3259 kmalloc include/linux/slab.h:590 [inline] io_add_buffers fs/io_uring.c:4405 [inline] io_provide_buffers fs/io_uring.c:4439 [inline] io_issue_sqe+0x2887/0x7010 fs/io_uring.c:6705 __io_queue_sqe fs/io_uring.c:6978 [inline] io_queue_sqe fs/io_uring.c:7020 [inline] io_submit_sqe fs/io_uring.c:7223 [inline] io_submit_sqes+0x1bca/0x8a20 fs/io_uring.c:7329 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10043 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f91ff527ae9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f91fca9d188 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007f91ff63af60 RCX: 00007f91ff527ae9 RDX: 0000000000000000 RSI: 00000000000002ff RDI: 0000000000000006 RBP: 00007f91ff581f25 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd59c6740f R14: 00007f91fca9d300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 16892 Comm: kworker/u4:7 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound io_ring_exit_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:unwind_next_frame+0xea9/0x1ce0 arch/x86/kernel/unwind_orc.c:616 Code: 7e 34 4c 89 f7 4c 01 e6 e8 24 f0 ff ff 84 c0 0f 84 10 f5 ff ff 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 0f b6 04 02 <84> c0 74 08 3c 03 0f 8e 90 0a 00 00 41 3b 2e 0f 84 b9 05 00 00 bf RSP: 0018:ffffc900055ff638 EFLAGS: 00000216 RAX: 0000000000000000 RBX: 1ffff92000abfecf RCX: 0000000000000003 RDX: 1ffff92000abfee2 RSI: 0000000000000001 RDI: ffffc900055ff768 RBP: 0000000000000001 R08: ffffffff8dee9bc6 R09: 0000000000000001 R10: fffff52000abfeed R11: 0000000000086089 R12: ffffc900055ff838 R13: ffffc900055ff745 R14: ffffc900055ff710 R15: ffffffff8dee9bca arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 slab_free mm/slub.c:3513 [inline] kfree+0xf6/0x560 mm/slub.c:4561 __io_remove_buffers.part.0+0x115/0x220 fs/io_uring.c:4327 __io_remove_buffers fs/io_uring.c:9263 [inline] io_destroy_buffers fs/io_uring.c:9263 [inline] io_ring_ctx_free fs/io_uring.c:9319 [inline] io_ring_exit_work+0x74d/0xbe8 fs/io_uring.c:9495 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 85 ed test %rbp,%rbp 5: 48 0f 44 eb cmove %rbx,%rbp 9: e8 3f 3c e1 ff callq 0xffe13c4d e: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 15: fc ff df 18: 48 8d bd 20 04 00 00 lea 0x420(%rbp),%rdi 1f: 48 89 fa mov %rdi,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2a: 0f 85 05 02 00 00 jne 0x235 <-- trapping instruction 30: 48 83 bd 20 04 00 00 cmpq $0x0,0x420(%rbp) 37: 00 38: 74 42 je 0x7c 3a: e8 0e 3c e1 ff callq 0xffe13c4d 3f: 4c rex.WR