rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=283101, q=135) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295129156-4295118654), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g283101 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28944 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: NMI backtrace for cpu 0 CPU: 0 PID: 16340 Comm: syz-executor.3 Not tainted 5.16.0-rc4-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_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x2125/0x2200 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:1428 __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:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200 Code: 48 89 ef 5d e9 f1 c4 45 00 5d be 03 00 00 00 e9 06 c2 63 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 8b 05 89 8b 8b 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b RSP: 0018:ffffc90000007c48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888080e9b740 RCX: ffff88801a4ba000 RDX: 0000000000000000 RSI: ffff88801a4ba000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000400 R09: 0000000000000000 R10: ffffffff875d7678 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff888076b46b00 R14: 0000000000000400 R15: ffff888076b46b00 pie_calculate_probability+0x674/0x7c0 net/sched/sch_pie.c:321 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:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 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_release+0x6f/0x720 kernel/locking/lockdep.c:5645 Code: 20 f0 f2 5b 81 c7 00 f1 f1 f1 f1 c7 40 04 f1 f1 04 f2 c7 40 08 04 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 88 00 00 00 <31> c0 0f 1f 44 00 00 65 8b 1d 1b 22 a6 7e 83 fb 07 0f 87 f6 04 00 RSP: 0018:ffffc9000ce67080 EFLAGS: 00000286 RAX: da78a7b47408c700 RBX: ffff88807ec8a000 RCX: ffff88801fcdbe7c RDX: 0000000000000000 RSI: ffffffff8212bab0 RDI: ffff88807ec8a358 RBP: 1ffff920019cce12 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8212b9a8 R11: 0000000000000000 R12: ffff88807ec8a358 R13: ffff88801fcdbe60 R14: ffff88814b23a4d0 R15: ffff88814b23a4d8 __raw_write_unlock include/linux/rwlock_api_smp.h:216 [inline] _raw_write_unlock+0x12/0x40 kernel/locking/spinlock.c:332 mb_set_largest_free_order+0x6b0/0x860 fs/ext4/mballoc.c:1102 mb_mark_used+0x9aa/0xdc0 fs/ext4/mballoc.c:1996 ext4_mb_use_best_found+0x207/0x8e0 fs/ext4/mballoc.c:2019 ext4_mb_measure_extent fs/ext4/mballoc.c:2126 [inline] ext4_mb_complex_scan_group+0x6dd/0x9e0 fs/ext4/mballoc.c:2365 ext4_mb_regular_allocator+0xdb0/0x3870 fs/ext4/mballoc.c:2778 ext4_mb_new_blocks+0x24d2/0x51f0 fs/ext4/mballoc.c:5586 ext4_ext_map_blocks+0x1fa3/0x5fd0 fs/ext4/extents.c:4285 ext4_map_blocks+0x653/0x17d0 fs/ext4/inode.c:637 ext4_getblk+0x144/0x6b0 fs/ext4/inode.c:847 ext4_bread+0x2a/0x1c0 fs/ext4/inode.c:900 ext4_append+0x177/0x3a0 fs/ext4/namei.c:67 ext4_init_new_dir+0x33f/0x5e0 fs/ext4/namei.c:2893 ext4_mkdir+0x3cf/0xb20 fs/ext4/namei.c:2939 vfs_mkdir+0x1c3/0x3b0 fs/namei.c:3883 do_mkdirat+0x285/0x300 fs/namei.c:3909 __do_sys_mkdir fs/namei.c:3929 [inline] __se_sys_mkdir fs/namei.c:3927 [inline] __x64_sys_mkdir+0xf2/0x140 fs/namei.c:3927 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: 0033:0x7f6bf8472af9 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:00007f6bf73e8188 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f6bf8585f60 RCX: 00007f6bf8472af9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000600 RBP: 00007f6bf84ccff7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffb9bd178f R14: 00007f6bf73e8300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 48 89 ef mov %rbp,%rdi 3: 5d pop %rbp 4: e9 f1 c4 45 00 jmpq 0x45c4fa 9: 5d pop %rbp a: be 03 00 00 00 mov $0x3,%esi f: e9 06 c2 63 02 jmpq 0x263c21a 14: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 1a: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 21: e8 b4 ff ff ff callq 0xffffffda 26: 31 c0 xor %eax,%eax 28: c3 retq 29: 90 nop * 2a: 65 8b 05 89 8b 8b 7e mov %gs:0x7e8b8b89(%rip),%eax # 0x7e8b8bba <-- trapping instruction 31: 89 c1 mov %eax,%ecx 33: 48 8b 34 24 mov (%rsp),%rsi 37: 81 e1 00 01 00 00 and $0x100,%ecx 3d: 65 gs 3e: 48 rex.W 3f: 8b .byte 0x8b