rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=e76/1/0x4000000000000002 softirq=10901/10901 fqs=1 (t=10500 jiffies g=5913 q=48) rcu: rcu_preempt kthread starved for 10498 jiffies! g5913 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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 1 CPU: 1 PID: 8064 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+0x31/0x50 kernel/kcov.c:107 Code: 0c 25 c0 1d 02 00 65 8b 15 b8 81 8b 7e f7 c2 00 01 1f 00 75 2c 8b 91 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 RSP: 0018:ffffc900027275f0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81486ea4 RBX: ffffea000289f9c0 RCX: ffff88806c3a8040 RDX: ffffc90001f89000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: ffffc90002727630 R08: 000000000003a768 R09: ffffed10150fe287 R10: ffffed10150fe287 R11: 0000000000000000 R12: ffff88809fbb5020 R13: dffffc0000000000 R14: 1ffff11013f76a04 R15: ffff8880a87f1428 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_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:lock_release+0x4c7/0x780 kernel/locking/lockdep.c:4506 Code: 48 c1 e8 03 80 3c 10 00 74 0c 48 c7 c7 28 96 0a 89 e8 9d 5b 56 00 48 83 3d bd de ae 07 00 0f 84 8c 02 00 00 48 8b 7d 88 57 9d <0f> 1f 44 00 00 65 48 8b 04 25 28 00 00 00 48 3b 45 d0 0f 85 70 02 RSP: 0018:ffffc90002727848 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff12152c5 RBX: ffff88806c3a88c8 RCX: ffffffff815bbb47 RDX: dffffc0000000000 RSI: ffff88806c3a88f8 RDI: 0000000000000286 RBP: ffffc900027278c8 R08: dffffc0000000000 R09: fffffbfff12877ed R10: fffffbfff12877ed R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffffffffffff R15: 000000000002002b rcu_lock_release+0x10/0x20 include/linux/rcupdate.h:213 rcu_read_unlock include/linux/rcupdate.h:671 [inline] memcg_kmem_get_cache+0x335/0x590 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 __d_alloc+0x2d/0x6e0 fs/dcache.c:1688 d_alloc_anon+0x17/0x20 fs/dcache.c:1786 __ns_get_path+0x36e/0x5e0 fs/nsfs.c:89 ns_get_path_cb fs/nsfs.c:116 [inline] ns_get_path+0x66/0x90 fs/nsfs.c:142 proc_ns_get_link+0xa2/0x180 fs/proc/namespaces.c:55 get_link fs/namei.c:1075 [inline] trailing_symlink+0x5a2/0xbc0 fs/namei.c:2257 path_openat+0x30f2/0x44a0 fs/namei.c:3531 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: 0033:0x414411 Code: 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 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fd6ef1ebc10 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000414411 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00000000004bf3b9 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007fd6ef1ec6d4 R13: 00000000004ca84d R14: 00000000004e3c70 R15: 00000000ffffffff