rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3028/1:b..l (detected by 1, t=10502 jiffies, g=8097, q=592) task:udevd state:R running task stack:24512 pid: 3028 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:193 Code: 1f 84 00 00 00 00 00 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 08 ed 68 0c 48 89 de 5b e9 c7 fc 48 00 cc cc cc cc cc cc cc <48> 8b 04 24 65 48 8b 0d 54 0e 82 7e 65 8b 15 55 0e 82 7e f7 c2 00 RSP: 0018:ffffc90002da77b0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff8880187c91e0 RCX: 0000000080000000 RDX: ffff88807d4ed940 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff81dc301a R09: fffff520000f159d R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880187c91e0 R13: ffff88801f0a4758 R14: 00000000ef19cbd6 R15: dffffc0000000000 hlist_bl_first_rcu include/linux/rculist_bl.h:24 [inline] __d_lookup+0x17f/0x730 fs/dcache.c:2430 lookup_fast+0xdc/0x7b0 fs/namei.c:1621 walk_component+0x115/0x610 fs/namei.c:1972 link_path_walk+0x642/0xd90 path_lookupat+0xa9/0x450 fs/namei.c:2454 filename_lookup+0x230/0x5c0 fs/namei.c:2484 user_path_at_empty+0x40/0x180 fs/namei.c:2883 do_readlinkat+0x114/0x3a0 fs/stat.c:442 __do_sys_readlink fs/stat.c:475 [inline] __se_sys_readlink fs/stat.c:472 [inline] __x64_sys_readlink+0x7b/0x90 fs/stat.c:472 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: 0033:0x7f56688f4d47 RSP: 002b:00007ffd5c6daa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007ffd5c6daa88 RCX: 00007f56688f4d47 RDX: 0000000000000400 RSI: 00007ffd5c6daa88 RDI: 00007ffd5c6daf68 RBP: 0000000000000400 R08: 0000561307f09c24 R09: 0000000000000000 R10: 0000000000000812 R11: 0000000000000246 R12: 00007ffd5c6daf68 R13: 00007ffd5c6daed8 R14: 0000561307ee5910 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10401 jiffies! g8097 f0x0 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:26144 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562 vkms_vblank_simulate: vblank timer overrun