rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=8e5/1/0x4000000000000000 softirq=147910/147911 fqs=13 (t=10500 jiffies g=260533 q=98) rcu: rcu_preempt kthread starved for 10466 jiffies! g260533 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:28688 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 22417 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode+0x7/0x40 kernel/kcov.c:166 Code: 00 e9 59 fe ff ff 48 8b 7c 24 08 e8 03 c2 46 00 e9 61 fd ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 65 8b 05 49 db 8a 7e <89> c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b RSP: 0018:ffffc90000dc0ea8 EFLAGS: 00000002 RAX: 0000000000010002 RBX: 0040e4fcc3f56980 RCX: 0000000000000018 RDX: ffff88808531ba00 RSI: ffff88808531ba00 RDI: 0000000000000003 RBP: 00000000000725d4 R08: 000000000000003f R09: 0000000000000000 R10: ffffffff8167c142 R11: 0000000000000000 R12: 0000000000000018 R13: 00000000000725d4 R14: 000001fb6d19e116 R15: dffffc0000000000 FS: 00007f4d6401d700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33522000 CR3: 0000000096a0b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:287 timekeeping_delta_to_ns kernel/time/timekeeping.c:377 [inline] timekeeping_get_ns kernel/time/timekeeping.c:387 [inline] ktime_get_update_offsets_now+0x2e2/0x5c0 kernel/time/timekeeping.c:2300 hrtimer_update_base kernel/time/hrtimer.c:631 [inline] hrtimer_interrupt+0x142/0x790 kernel/time/hrtimer.c:1793 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:trylock_clear_pending kernel/locking/qspinlock_paravirt.h:121 [inline] RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:435 [inline] RIP: 0010:__pv_queued_spin_lock_slowpath+0x3c4/0xb40 kernel/locking/qspinlock.c:508 Code: 00 48 c1 e9 03 83 e3 07 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 2c 01 eb 0c f3 90 41 83 ec 01 0f 84 72 04 00 00 <41> 0f b6 45 00 38 d8 7f 08 84 c0 0f 85 91 05 00 00 0f b6 45 00 84 RSP: 0018:ffffc90012ee7cc8 EFLAGS: 00000202 RAX: 0000000000000003 RBX: 0000000000000000 RCX: 1ffff11002ff2b60 RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff888017f95b00 R08: 0000000000000001 R09: ffffffff8ff72a0f R10: 0000000000000001 R11: 0000000000000000 R12: 000000000000269b R13: ffffed1002ff2b60 R14: 0000000000000001 R15: ffff8880b9d3a880 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:349 [inline] fast_dput fs/dcache.c:764 [inline] fast_dput fs/dcache.c:740 [inline] dput+0x4ac/0xbc0 fs/dcache.c:875 path_put+0x2d/0x60 fs/namei.c:557 do_mount fs/namespace.c:3332 [inline] __do_sys_mount fs/namespace.c:3539 [inline] __se_sys_mount fs/namespace.c:3516 [inline] __x64_sys_mount+0x28a/0x300 fs/namespace.c:3516 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: 0033:0x7f4d66aa7ae9 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:00007f4d6401d188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f4d66bbaf60 RCX: 00007f4d66aa7ae9 RDX: 0000000000000000 RSI: 0000000020000200 RDI: 00000000200002c0 RBP: 00007f4d66b01f6d R08: 0000000020000280 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4d670eeb2f R14: 00007f4d6401d300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 22413 Comm: syz-executor.1 Not tainted 5.16.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 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+0x40/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline] RIP: 0010:div_u64 include/linux/math64.h:128 [inline] RIP: 0010:pie_calculate_probability+0x27d/0x7c0 net/sched/sch_pie.c:348 Code: 89 c6 4c 89 6c 24 38 e8 d1 3c 1a fa 47 8d 24 a4 31 d2 4c 89 ff 43 8d 0c 24 48 c1 ed 02 48 b8 ff ff ff ff ff ff ff 00 48 f7 f1 <49> 89 c5 48 89 c6 48 c1 eb 02 49 89 cc e8 11 40 1a fa 4d 39 ef 73 RSP: 0018:ffffc90000007c50 EFLAGS: 00000207 RAX: 00000001ad7f29ab RBX: 0000000000abcc77 RCX: 0000000000989680 RDX: 000000000078f87f RSI: ffffffff875d5c8f RDI: 0000000000000000 RBP: 0000000000044b82 R08: 00000000000f4240 R09: 0000000000000000 R10: ffffffff875d5cd6 R11: 0000000000000000 R12: 00000000004c4b40 R13: 00000010c6f7a0b5 R14: 0000000000000001 R15: 0000000000000000 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_is_held_type+0xff/0x140 kernel/locking/lockdep.c:5685 Code: 00 00 b8 ff ff ff ff 65 0f c1 05 3c 68 be 76 83 f8 01 75 29 9c 58 f6 c4 02 75 3d 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 ed eb b9 0f 0b 48 RSP: 0018:ffffc90012ea7c30 EFLAGS: 00000296 RAX: 0000000000000046 RBX: 0000000000000003 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000000 RBP: ffffffff8bb83be0 R08: 0000000000000000 R09: ffffffff8d912b97 R10: fffffbfff1b22572 R11: 000000000000006e R12: ffff888085b61d00 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff888085b627b0 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5608 __raw_spin_trylock include/linux/spinlock_api_smp.h:90 [inline] _raw_spin_trylock+0x60/0x70 kernel/locking/spinlock.c:138 spin_trylock include/linux/spinlock.h:359 [inline] dentry_kill fs/dcache.c:697 [inline] dput+0x643/0xbc0 fs/dcache.c:888 lookup_dcache+0xef/0x130 fs/namei.c:1526 __lookup_hash+0x29/0x180 fs/namei.c:1543 do_rmdir+0x22c/0x430 fs/namei.c:4018 __do_sys_rmdir fs/namei.c:4049 [inline] __se_sys_rmdir fs/namei.c:4047 [inline] __x64_sys_rmdir+0xc6/0x110 fs/namei.c:4047 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: 0033:0x7f1d26db2ae9 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:00007f1d24328188 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 00007f1d26ec5f60 RCX: 00007f1d26db2ae9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180 RBP: 00007f1d26e0cf6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1d273f9b2f R14: 00007f1d24328300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e9 59 fe ff ff jmpq 0xfffffe5e 5: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi a: e8 03 c2 46 00 callq 0x46c212 f: e9 61 fd ff ff jmpq 0xfffffd75 14: cc int3 15: cc int3 16: cc int3 17: cc int3 18: cc int3 19: cc int3 1a: cc int3 1b: cc int3 1c: cc int3 1d: cc int3 1e: cc int3 1f: cc int3 20: cc int3 21: cc int3 22: 65 8b 05 49 db 8a 7e mov %gs:0x7e8adb49(%rip),%eax # 0x7e8adb72 * 29: 89 c2 mov %eax,%edx <-- trapping instruction 2b: 81 e2 00 01 00 00 and $0x100,%edx 31: a9 00 01 ff 00 test $0xff0100,%eax 36: 74 10 je 0x48 38: 31 c0 xor %eax,%eax 3a: 85 d2 test %edx,%edx 3c: 74 15 je 0x53 3e: 8b .byte 0x8b