rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=f87/1/0x4000000000000000 softirq=240125/240125 fqs=0 (detected by 1, t=10502 jiffies, g=419801, q=1485) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2974 Comm: systemd-udevd Not tainted 5.15.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0xe61/0x54a0 kernel/locking/lockdep.c:5042 Code: 30 48 c7 04 03 00 00 00 00 48 8b 84 24 e0 00 00 00 65 48 2b 04 25 28 00 00 00 0f 85 1e 2f 00 00 48 81 c4 e8 00 00 00 44 89 f0 <5b> 5d 41 5c 41 5d 41 5e 41 5f c3 e8 8f 61 7c 02 85 c0 0f 84 b9 f8 RSP: 0018:ffffc90000007bf8 EFLAGS: 00000082 RAX: 0000000000000001 RBX: 1ffff92000000f73 RCX: ffffffff815b260f RDX: 1ffff1100409615b RSI: 0000000000000001 RDI: ffffffff8f05e4f8 RBP: 000000000000c199 R08: 0000000000000000 R09: ffffffff8fd059e7 R10: fffffbfff1fa0b3c R11: 0000000000000000 R12: ffff8880204b0b30 R13: ffff8880204b00c0 R14: 0000000000000001 R15: a44371ab51f8558f FS: 00007fe46b11a8c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6de2b20180 CR3: 0000000020794000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000006 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 debug_object_deactivate lib/debugobjects.c:735 [inline] debug_object_deactivate+0x101/0x300 lib/debugobjects.c:723 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate kernel/time/hrtimer.c:481 [inline] __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x3f8/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:prefetchw arch/x86/include/asm/processor.h:742 [inline] RIP: 0010:slab_alloc mm/slab.c:3319 [inline] RIP: 0010:__do_kmalloc mm/slab.c:3700 [inline] RIP: 0010:__kmalloc+0x1bd/0x4d0 mm/slab.c:3711 Code: 00 00 48 83 3c 24 00 48 89 54 24 18 0f 85 f1 01 00 00 9c 58 f6 c4 02 0f 85 10 02 00 00 48 83 3c 24 00 74 01 fb 48 8b 74 24 18 <0f> 0d 0e 0f 1f 44 00 00 48 83 7b 50 00 0f 84 81 00 00 00 44 23 3d RSP: 0018:ffffc90002ba79f8 EFLAGS: 00000206 RAX: 0000000000000002 RBX: ffff888010c40900 RCX: 1ffffffff1adc2e1 RDX: 0000000000000000 RSI: ffff88803fd74000 RDI: 0000000000000000 RBP: ffffffff83a9d613 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c4dd8 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000001000 R14: 0000000000000c40 R15: 0000000000000c40 kmalloc include/linux/slab.h:596 [inline] tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x21b/0x400 security/tomoyo/file.c:822 security_inode_getattr+0xcf/0x140 security/security.c:1333 vfs_getattr fs/stat.c:157 [inline] vfs_statx+0x164/0x390 fs/stat.c:225 vfs_fstatat fs/stat.c:243 [inline] vfs_lstat include/linux/fs.h:3356 [inline] __do_sys_newlstat+0x91/0x110 fs/stat.c:398 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fe469f8c335 Code: 69 db 2b 00 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 83 ff 01 48 89 f0 77 30 48 89 c7 48 89 d6 b8 06 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 f3 c3 90 48 8b 15 31 db 2b 00 f7 d8 64 89 RSP: 002b:00007ffd7f6ed5a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 RAX: ffffffffffffffda RBX: 000055b7ec4047e0 RCX: 00007fe469f8c335 RDX: 00007ffd7f6ed5e0 RSI: 00007ffd7f6ed5e0 RDI: 000055b7ec4037e0 RBP: 00007ffd7f6ed6a0 R08: 00007fe46a24b1c8 R09: 0000000000001010 R10: 00007fe46a24ab58 R11: 0000000000000246 R12: 000055b7ec4037e0 R13: 000055b7ec40380a R14: 000055b7ec401231 R15: 000055b7ec40123a rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g419801 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=152738 rcu: rcu_preempt kthread starved for 10502 jiffies! g419801 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27336 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: ---------------- Code disassembly (best guess): 0: 30 48 c7 xor %cl,-0x39(%rax) 3: 04 03 add $0x3,%al 5: 00 00 add %al,(%rax) 7: 00 00 add %al,(%rax) 9: 48 8b 84 24 e0 00 00 mov 0xe0(%rsp),%rax 10: 00 11: 65 48 2b 04 25 28 00 sub %gs:0x28,%rax 18: 00 00 1a: 0f 85 1e 2f 00 00 jne 0x2f3e 20: 48 81 c4 e8 00 00 00 add $0xe8,%rsp 27: 44 89 f0 mov %r14d,%eax * 2a: 5b pop %rbx <-- trapping instruction 2b: 5d pop %rbp 2c: 41 5c pop %r12 2e: 41 5d pop %r13 30: 41 5e pop %r14 32: 41 5f pop %r15 34: c3 retq 35: e8 8f 61 7c 02 callq 0x27c61c9 3a: 85 c0 test %eax,%eax 3c: 0f .byte 0xf 3d: 84 .byte 0x84 3e: b9 .byte 0xb9 3f: f8 clc