rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3560/1:b..l P6444/1:b..l (detected by 0, t=10502 jiffies, g=21413, q=119) task:syz.7.509 state:R running task stack:28800 pid: 6444 ppid: 5778 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681 RIP: 0010:__dentry_path+0x2af/0x5c0 fs/d_path.c:344 Code: ff df 0f 8e d4 01 00 00 49 ff cf 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 75 55 41 c6 07 2f 49 8d 7e 50 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 55 e3 e7 ff ff cd 4d 8b 6e 50 4d 39 ee 0f RSP: 0018:ffffc90003aaf968 EFLAGS: 00000a06 RAX: 1ffff11028100182 RBX: 0000000000001818 RCX: ffff88802215bb80 RDX: 0000000000000000 RSI: 0000000000000ff9 RDI: ffff888140800c10 RBP: 0000000000000ff9 R08: dffffc0000000000 R09: fffffbfff1ad32b6 R10: fffffbfff1ad32b6 R11: 1ffffffff1ad32b5 R12: 0000000000000004 R13: dffffc0000000000 R14: ffff888140800bc0 R15: ffff8880224c2ff8 dentry_path_raw+0x80/0xc0 fs/d_path.c:369 tomoyo_get_dentry_path security/tomoyo/realpath.c:131 [inline] tomoyo_get_local_path+0xce/0x740 security/tomoyo/realpath.c:157 tomoyo_realpath_from_path+0x2dc/0x610 security/tomoyo/realpath.c:-1 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x1d5/0x5d0 security/tomoyo/file.c:723 security_file_ioctl+0x6c/0xa0 security/security.c:1555 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl+0x48/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fa3d6981acb RSP: 002b:00007fa3d4be9050 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa3d6bd9038 RCX: 00007fa3d6981acb RDX: 0000000000000000 RSI: 0000000000006364 RDI: 00000000000000d8 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff43a57f97 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fa3d6bd9038 R14: 00007fff43a57eb0 R15: 00007fff43a57f98 task:udevd state:R running task stack:23296 pid: 3560 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc90002e8f838 EFLAGS: 00000206 RAX: 52eeddf69a93ec00 RBX: ffff88807d465940 RCX: 52eeddf69a93ec00 RDX: 0000000000000000 RSI: ffffffff8a0b2ac0 RDI: ffffffff8a59a4c0 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffff52000031cec R10: fffff52000031cec R11: 1ffff92000031ceb R12: 0000000000000000 R13: 0000000000000246 R14: ffffffff8c11c660 R15: ffff88807d466430 hlist_bl_first_rcu include/linux/rculist_bl.h:24 [inline] __d_lookup+0x162/0x760 fs/dcache.c:2430 lookup_fast+0xd7/0x710 fs/namei.c:1621 walk_component+0x81/0x460 fs/namei.c:1972 link_path_walk+0x662/0xd40 fs/namei.c:-1 path_lookupat+0x9d/0x440 fs/namei.c:2454 filename_lookup+0x1e2/0x4f0 fs/namei.c:2484 user_path_at_empty+0x40/0x190 fs/namei.c:2883 do_readlinkat+0xd4/0x480 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+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f0dca1353a7 RSP: 002b:00007fff42556de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007fff425572c0 RCX: 00007f0dca1353a7 RDX: 0000000000000400 RSI: 00007fff42556df0 RDI: 00007fff425572c0 RBP: 00007fff42556df0 R08: 00000000000001e0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400 R13: 000055b9b2c75100 R14: 000055b9d4f278c0 R15: 00007fff42557cf0 rcu: rcu_preempt kthread starved for 10322 jiffies! g21413 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:27496 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 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 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729