rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19420/1:b..l (detected by 0, t=10502 jiffies, g=56885, q=22) task:systemd-udevd state:R running task stack:25552 pid:19420 ppid: 2971 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6687 irqentry_exit+0x56/0x90 kernel/entry/common.c:425 asm_sysvec_reschedule_ipi+0x12/0x20 RIP: 0010:find_lock_entries+0x3e4/0x1120 mm/filemap.c:2106 Code: 8b 2b 4c 89 ef 48 8b 5c 24 50 48 89 de e8 e4 b7 d6 ff 49 39 dd 0f 83 22 01 00 00 e8 96 b5 d6 ff e9 f5 02 00 00 e8 8c b5 d6 ff <48> b8 00 00 00 00 00 fc ff df 48 8b 4c 24 40 80 3c 01 00 74 0a 48 RSP: 0018:ffffc9001882f620 EFLAGS: 00000293 RAX: ffffffff81acdb05 RBX: 1ffffd40001f01c1 RCX: ffff888018900000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9001882f770 R08: ffffffff81acc532 R09: fffff940001f01c1 R10: fffff940001f01c1 R11: 0000000000000000 R12: ffffea0000f80e00 R13: ffffea0000f83048 R14: 00fff0000008003d R15: ffffea0000f80e00 shmem_undo_range+0x2bd/0x1c30 mm/shmem.c:938 shmem_truncate_range mm/shmem.c:1058 [inline] shmem_evict_inode+0x22e/0xa50 mm/shmem.c:1140 evict+0x2a4/0x620 fs/inode.c:588 __dentry_kill+0x3b8/0x5b0 fs/dcache.c:582 dput+0x44e/0x6e0 fs/dcache.c:888 do_renameat2+0xab8/0x1450 fs/namei.c:4781 __do_sys_rename fs/namei.c:4825 [inline] __se_sys_rename fs/namei.c:4823 [inline] __x64_sys_rename+0x82/0x90 fs/namei.c:4823 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f696db11d47 RSP: 002b:00007ffe5d5d0668 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 0000562da45fdff0 RCX: 00007f696db11d47 RDX: 0000000000000000 RSI: 00007ffe5d5d0670 RDI: 0000562da45fd060 RBP: 00007ffe5d5d0730 R08: 0000562da45fe410 R09: 0000562da45fe330 R10: 00007f696ed168c0 R11: 0000000000000246 R12: 00007ffe5d5d0670 R13: 0000000000000001 R14: 0000562da3fb76cb R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10502 jiffies! g56885 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26544 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 preempt_schedule_common kernel/sched/core.c:6459 [inline] preempt_schedule+0x14d/0x190 kernel/sched/core.c:6484 preempt_schedule_thunk+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 prepare_to_swait_event+0x322/0x340 kernel/sched/swait.c:120 rcu_gp_fqs_loop+0x216/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 19411 Comm: syz-executor.3 Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:write_comp_data kernel/kcov.c:217 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x4/0x90 kernel/kcov.c:291 Code: c1 e0 03 48 83 c8 18 48 89 34 01 4c 89 44 f9 18 49 ff c2 4c 89 11 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 4c 8b 04 24 <65> 48 8b 14 25 c0 ef 01 00 65 8b 05 64 61 7e 7e a9 00 01 ff 00 74 RSP: 0018:ffffc90000dc08c0 EFLAGS: 00000046 RAX: ffffffff81a540a7 RBX: 1ffff920001b813c RCX: ffff888041b9d580 RDX: 0000000080010000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000dc0b40 R08: ffffffff81a54103 R09: ffffed10173a64a2 R10: ffffed10173a64a2 R11: 0000000000000000 R12: ffffc90000dc0b40 R13: ffffc90000dc09e6 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f190b714700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdb03f0b020 CR3: 0000000085119000 CR4: 00000000003526e0 Call Trace: perf_prepare_sample+0xf63/0x1770 kernel/events/core.c:7438 __perf_event_output kernel/events/core.c:7487 [inline] perf_event_output_forward+0x176/0x2c0 kernel/events/core.c:7507 __perf_event_overflow+0x1f8/0x380 kernel/events/core.c:9177 perf_swevent_hrtimer+0x3d1/0x530 kernel/events/core.c:10567 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:lock_acquire+0x21f/0x4d0 kernel/locking/lockdep.c:5629 Code: 08 4c 89 f7 e8 32 e5 69 00 f6 84 24 81 00 00 00 02 0f 85 13 02 00 00 41 f7 c4 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 43 c7 44 2f 09 00 00 00 00 43 c7 44 2f 11 RSP: 0018:ffffc900187ef440 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920030fde98 RCX: ffff888041b9df98 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900187ef590 R08: dffffc0000000000 R09: fffffbfff1fa35db R10: fffffbfff1fa35db R11: 0000000000000000 R12: 0000000000000246 R13: 1ffff920030fde90 R14: ffffc900187ef4c0 R15: dffffc0000000000 fs_reclaim_acquire+0x9b/0x110 mm/page_alloc.c:4556 might_alloc include/linux/sched/mm.h:198 [inline] slab_pre_alloc_hook mm/slab.h:492 [inline] slab_alloc_node mm/slub.c:3120 [inline] slab_alloc mm/slub.c:3214 [inline] kmem_cache_alloc_trace+0x42/0x310 mm/slub.c:3231 kmalloc include/linux/slab.h:591 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x9e3/0xdd0 drivers/tty/tty_io.c:2140 chrdev_open+0x5fb/0x680 fs/char_dev.c:414 do_dentry_open+0x7cb/0x1020 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x28b4/0x3670 fs/namei.c:3561 do_filp_open+0x277/0x4f0 fs/namei.c:3588 do_sys_openat2+0x13b/0x500 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1227 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f190e19ea39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f190b714188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f190e2a1f60 RCX: 00007f190e19ea39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f190e1f8c5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffda2d3680f R14: 00007f190b714300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 8b 2b mov (%rbx),%ebp 2: 4c 89 ef mov %r13,%rdi 5: 48 8b 5c 24 50 mov 0x50(%rsp),%rbx a: 48 89 de mov %rbx,%rsi d: e8 e4 b7 d6 ff callq 0xffd6b7f6 12: 49 39 dd cmp %rbx,%r13 15: 0f 83 22 01 00 00 jae 0x13d 1b: e8 96 b5 d6 ff callq 0xffd6b5b6 20: e9 f5 02 00 00 jmpq 0x31a 25: e8 8c b5 d6 ff callq 0xffd6b5b6 * 2a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax <-- trapping instruction 31: fc ff df 34: 48 8b 4c 24 40 mov 0x40(%rsp),%rcx 39: 80 3c 01 00 cmpb $0x0,(%rcx,%rax,1) 3d: 74 0a je 0x49 3f: 48 rex.W