rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15800/1:b..l P3935/1:b..l (detected by 0, t=10502 jiffies, g=53433, q=299 ncpus=2) task:udevd state:R running task stack:0 pid:3935 ppid:1 flags:0x00000004 Call trace: __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555 context_switch kernel/sched/core.c:5245 [inline] __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562 preempt_schedule_common+0xec/0x1a0 kernel/sched/core.c:6731 preempt_schedule+0x64/0x84 kernel/sched/core.c:6755 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xa8/0xac kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11c/0x180 kernel/sched/wait.c:208 sock_def_readable+0x150/0x278 net/core/sock.c:3316 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_sendskb+0xa4/0x160 net/netlink/af_netlink.c:1270 netlink_unicast+0x2c4/0x814 net/netlink/af_netlink.c:1359 netlink_sendmsg+0x6f4/0x9c0 net/netlink/af_netlink.c:1872 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518 ___sys_sendmsg net/socket.c:2572 [inline] __sys_sendmsg+0x288/0x374 net/socket.c:2601 __do_sys_sendmsg net/socket.c:2610 [inline] __se_sys_sendmsg net/socket.c:2608 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 task:udevd state:R running task stack:0 pid:15800 ppid:3935 flags:0x00000004 Call trace: __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555 context_switch kernel/sched/core.c:5245 [inline] __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562 preempt_schedule_irq+0x8c/0x1ac kernel/sched/core.c:6874 arm64_preempt_schedule_irq+0x44/0x54 arch/arm64/kernel/entry-common.c:265 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline] el1_interrupt+0x3c/0x54 arch/arm64/kernel/entry-common.c:486 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline] read_seqbegin include/linux/seqlock.h:893 [inline] read_seqbegin_or_lock+0x14c/0x248 include/linux/seqlock.h:1187 prepend_path+0x148/0x9ec fs/d_path.c:165 d_absolute_path+0xa0/0x148 fs/d_path.c:233 tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline] tomoyo_realpath_from_path+0x258/0x4d4 security/tomoyo/realpath.c:271 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x19c/0x35c security/tomoyo/file.c:771 tomoyo_file_open+0x128/0x198 security/tomoyo/tomoyo.c:320 security_file_open+0x6c/0xac security/security.c:1681 do_dentry_open+0x29c/0xf98 fs/open.c:869 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 rcu: rcu_preempt kthread starved for 10502 jiffies! g53433 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:0 pid:16 ppid:2 flags:0x00000008 Call trace: __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555 context_switch kernel/sched/core.c:5245 [inline] __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562 preempt_schedule_common+0xec/0x1a0 kernel/sched/core.c:6731 preempt_schedule+0x64/0x84 kernel/sched/core.c:6755 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xa8/0xac kernel/locking/spinlock.c:194 debug_object_free+0x2a8/0x450 lib/debugobjects.c:855 destroy_timer_on_stack kernel/time/timer.c:812 [inline] schedule_timeout+0x1b0/0x2f4 kernel/time/timer.c:2172 rcu_gp_fqs_loop+0x2b4/0x1378 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xb4/0x2fc kernel/rcu/tree.c:1905 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 1: task:syz.4.3127 state:R running task stack:0 pid:15836 ppid:4321 flags:0x00000000 Call trace: __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555 0xffffe00018f31bb6