rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=446/1/0x4000000000000002 softirq=11553/11553 fqs=2784 (t=10501 jiffies g=6049 q=189) rcu: rcu_preempt kthread starved for 4933 jiffies! g6049 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 8147 Comm: syz-executor.0 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__sanitizer_cov_trace_pc+0x48/0x50 kernel/kcov.c:112 Code: 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 8d 7e 01 8b 89 84 13 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 4c 8b 04 24 65 48 8b 04 25 c0 1d 02 00 65 RSP: 0018:ffffc90001fe74a8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81486ea4 RBX: ffffea00023585c0 RCX: ffff888098cfc180 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00023585c0 RBP: ffffc90001fe74e8 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880936a4020 R13: dffffc0000000000 R14: 1ffff110126d4804 R15: ffff8880a85919e8 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_notrace+0xdb/0x120 kernel/sched/core.c:4309 ___preempt_schedule_notrace+0x16/0x27 arch/x86/entry/thunk_64.S:51 rcu_is_watching+0x82/0xa0 kernel/rcu/tree.c:923 rcu_read_unlock include/linux/rcupdate.h:667 [inline] memcg_kmem_get_cache+0x301/0x590 mm/memcontrol.c:2808 slab_pre_alloc_hook mm/slab.h:572 [inline] slab_alloc mm/slab.c:3306 [inline] kmem_cache_alloc+0x86/0x2e0 mm/slab.c:3484 proc_alloc_inode+0x1f/0xe0 fs/proc/inode.c:62 alloc_inode fs/inode.c:230 [inline] new_inode_pseudo+0x68/0x240 fs/inode.c:919 new_inode+0x28/0x1c0 fs/inode.c:948 proc_pid_make_inode+0x27/0x1d0 fs/proc/base.c:1754 proc_pid_instantiate+0x4f/0x1a0 fs/proc/base.c:3227 proc_pid_lookup+0x21f/0x300 fs/proc/base.c:3262 proc_root_lookup+0x22/0x50 fs/proc/root.c:248 __lookup_slow+0x285/0x380 fs/namei.c:1667 lookup_slow fs/namei.c:1684 [inline] walk_component+0x2d6/0x7b0 fs/namei.c:1804 link_path_walk+0x75b/0x1410 fs/namei.c:2121 path_openat+0x139/0x44a0 fs/namei.c:3528 do_filp_open+0x192/0x3d0 fs/namei.c:3559 do_sys_open+0x29f/0x560 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x87/0x90 fs/open.c:1110 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4143f0 Code: 05 48 3d 01 f0 ff ff 0f 83 2d 19 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 7d 40 66 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff RSP: 002b:00007fff36e2a798 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fff36e2a7c4 RCX: 00000000004143f0 RDX: 00007fff36e2a7ca RSI: 0000000000080001 RDI: 00000000004c00fb RBP: 00007fff36e2a7c0 R08: 0000000000000000 R09: 0000000000000004 R10: 0000000000000075 R11: 0000000000000246 R12: 00000000004c00fb R13: 00007fff36e2ace0 R14: 0000000000000000 R15: 00007fff36e2acf0