rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=c1f/1/0x4000000000000000 softirq=189091/189091 fqs=1 (t=10501 jiffies g=259193 q=625) rcu: rcu_preempt kthread starved for 10498 jiffies! g259193 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:I stack:28464 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4900 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: 19882 Comm: kworker/u4:12 Not tainted 5.16.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:200 Code: 00 00 e9 d6 39 64 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 f9 a7 8b 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc900104df9f0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffe8ffffc0b640 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff816b4fa0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816b4fc6 R11: 0000000000000000 R12: fffff91ffff816c9 R13: 0000000000000000 R14: ffffe8ffffc0b648 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002001d000 CR3: 000000000b88e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000009800 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:440 [inline] smp_call_function_many_cond+0x450/0xc20 kernel/smp.c:969 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1112 [inline] text_poke_bp_batch+0x1b3/0x560 arch/x86/kernel/alternative.c:1297 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_flush arch/x86/kernel/alternative.c:1448 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1da/0x400 kernel/jump_label.c:830 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:733 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:725 process_one_work+0x9b2/0x1660 kernel/workqueue.c:2298 worker_thread+0x65d/0x1130 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 0 CPU: 0 PID: 353 Comm: syz-executor.0 Not tainted 5.16.0-rc8-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+0x5c/0x759 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 0a e7 14 f8 48 89 ef e8 c2 5c 15 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 53 27 08 f8 65 8b 05 4c 7b bb 76 85 c0 74 0a 5b 5d c3 e8 c0 13 RSP: 0018:ffffc90000007c08 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff1ffa656 RDX: 0000000000000000 RSI: 0000000000000102 RDI: 0000000000000001 RBP: ffff8880b9c28280 R08: 0000000000000001 R09: ffffffff8ff7aaef R10: 0000000000000001 R11: 0000000000000000 R12: 0000000100023f45 R13: ffff8880b9c28280 R14: 0000000000000000 R15: 00000000ffffffff __mod_timer+0x837/0xe30 kernel/time/timer.c:1065 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x67c/0xa30 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:check_kcov_mode+0x7/0x40 kernel/kcov.c:166 Code: 00 e9 59 fe ff ff 48 8b 7c 24 08 e8 13 3f 46 00 e9 61 fd ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 65 8b 05 a9 ac 8b 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:ffffc9000541f570 EFLAGS: 00000207 RAX: 0000000000000001 RBX: 00000000000000a0 RCX: 00000000000000a0 RDX: 0000000000040000 RSI: ffff8881745f4000 RDI: 0000000000000003 RBP: ffff8881533c05e0 R08: 0000000000000093 R09: ffff8881533c0397 R10: ffffffff8210136e R11: 00000000ffff8000 R12: ffff8880878b1300 R13: ffff8881533c0390 R14: 00000000000000a0 R15: ffff8881533c037c write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:287 ext4_fill_raw_inode+0x8ee/0x1e90 fs/ext4/inode.c:4329 ext4_do_update_inode fs/ext4/inode.c:5094 [inline] ext4_mark_iloc_dirty+0x587/0x1cf0 fs/ext4/inode.c:5694 __ext4_mark_inode_dirty+0x220/0x8d0 fs/ext4/inode.c:5890 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5919 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2399 generic_update_time fs/inode.c:1782 [inline] inode_update_time fs/inode.c:1795 [inline] touch_atime+0x63d/0x700 fs/inode.c:1867 pick_link fs/namei.c:1751 [inline] step_into+0x109e/0x1c80 fs/namei.c:1826 walk_component+0x171/0x6a0 fs/namei.c:1976 link_path_walk.part.0+0x757/0xd00 fs/namei.c:2297 link_path_walk fs/namei.c:2222 [inline] path_parentat+0xb1/0x1c0 fs/namei.c:2496 filename_parentat+0x1bb/0x5a0 fs/namei.c:2519 filename_create+0xa1/0x480 fs/namei.c:3637 do_mkdirat+0x94/0x300 fs/namei.c:3898 __do_sys_mkdirat fs/namei.c:3924 [inline] __se_sys_mkdirat fs/namei.c:3922 [inline] __x64_sys_mkdirat+0x115/0x170 fs/namei.c:3922 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: 0033:0x7f1e06dc8e99 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:00007f1e0573e168 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f1e06edbf60 RCX: 00007f1e06dc8e99 RDX: 00000000000001ff RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007f1e06e22ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdc1d2233f R14: 00007f1e0573e300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: e9 d6 39 64 02 jmpq 0x26439dd 7: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) d: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 14: e8 b4 ff ff ff callq 0xffffffcd 19: 31 c0 xor %eax,%eax 1b: c3 retq 1c: 90 nop 1d: 65 8b 05 f9 a7 8b 7e mov %gs:0x7e8ba7f9(%rip),%eax # 0x7e8ba81d 24: 89 c1 mov %eax,%ecx 26: 48 8b 34 24 mov (%rsp),%rsi * 2a: 81 e1 00 01 00 00 and $0x100,%ecx <-- trapping instruction 30: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx 37: 02 00 39: a9 00 01 ff 00 test $0xff0100,%eax 3e: 74 0e je 0x4e