rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=781/1/0x4000000000000000 softirq=99370/99372 fqs=0 (t=10502 jiffies g=171425 q=200) rcu: rcu_preempt kthread starved for 10503 jiffies! g171425 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: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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.16.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0x452/0xc20 kernel/smp.c:969 Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 70 79 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 33 06 00 00 8b 43 08 31 RSP: 0018:ffffc90000eef9f8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffe8ffffc0b640 RCX: 0000000000000000 RDX: ffff888011c76200 RSI: ffffffff816b5970 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816b5996 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: 0000561861302e88 CR3: 000000000b88e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: 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+0x1d5/0x430 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:732 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:724 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 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: 32034 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:rcu_read_unlock_sched_notrace include/linux/rcupdate.h:810 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline] RIP: 0010:lock_acquire+0x44d/0x510 kernel/locking/lockdep.c:5608 Code: ff ff e8 95 58 a4 ff e9 59 fc ff ff 65 ff 05 4a 83 a6 7e 48 8b 05 43 ce 20 0c e8 3e c9 05 00 85 c0 74 17 65 ff 0d 33 83 a6 7e <0f> 85 78 fc ff ff e8 67 58 a4 ff e9 6e fc ff ff e8 ee f5 e7 07 85 RSP: 0018:ffffc90000007c48 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 1ffff92000000f8b RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000102 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8d90e597 R10: fffffbfff1b21cb2 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90000007d70 R15: 0000000000000000 call_timer_fn+0x12b/0x6b0 kernel/time/timer.c:1418 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:preempt_schedule_irq+0x49/0x90 kernel/sched/core.c:6668 Code: 55 53 65 48 8b 1c 25 40 70 02 00 48 89 dd 48 c1 ed 03 48 01 c5 bf 01 00 00 00 e8 d2 9a 09 f8 e8 4d 7f 37 f8 fb bf 01 00 00 00 12 a9 ff ff 9c 58 fa f6 c4 02 75 27 bf 01 00 00 00 e8 00 8a 09 RSP: 0018:ffffc90018a8f328 EFLAGS: 00000206 RAX: 0000000000523527 RBX: ffff888065584200 RCX: 1ffffffff1ff607e RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffed100cab0840 R08: 0000000000000001 R09: ffffffff8ff74a9f R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode+0x2e/0x40 kernel/kcov.c:177 Code: a1 8b 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 a4 15 00 00 85 d2 74 0b 8b 86 80 15 00 00 39 f8 <0f> 94 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 31 c0 65 8b RSP: 0018:ffffc90018a8f3f8 EFLAGS: 00000297 RAX: 0000000000000002 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff888065584200 RDI: 0000000000000003 RBP: ffffea0001559040 R08: 0000000000000000 R09: ffffea0001559047 R10: ffffffff81a582f9 R11: 0000000000000000 R12: ffffea0001559040 R13: 0000000000000000 R14: 0000000000000027 R15: 0000000000000000 write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_const_cmp8+0x1d/0x70 kernel/kcov.c:294 folio_flags.constprop.0+0x39/0x70 include/linux/page-flags.h:263 folio_test_swapbacked include/linux/page-flags.h:446 [inline] folio_test_swapcache include/linux/page-flags.h:487 [inline] folio_mapping+0x69/0x220 mm/util.c:719 invalidate_inode_page+0x18/0x410 mm/truncate.c:258 __invalidate_mapping_pages+0x234/0x500 mm/truncate.c:504 drop_pagecache_sb+0xcf/0x2a0 fs/drop_caches.c:39 iterate_supers+0x13c/0x290 fs/super.c:697 drop_caches_sysctl_handler+0xdb/0x110 fs/drop_caches.c:62 proc_sys_call_handler+0x437/0x620 fs/proc/proc_sysctl.c:586 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x472/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_iter_write+0x70/0xa0 fs/read_write.c:892 iter_file_splice_write+0x6fa/0xc10 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 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: 0033:0x7f7746209ae9 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:00007f774377f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f774631cf60 RCX: 00007f7746209ae9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007f7746263f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc0c41ca1f R14: 00007f774377f300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 0b 00 or (%rax),%eax 2: 85 ed test %ebp,%ebp 4: 74 4d je 0x53 6: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax d: fc ff df 10: 4d 89 f4 mov %r14,%r12 13: 4c 89 f5 mov %r14,%rbp 16: 49 c1 ec 03 shr $0x3,%r12 1a: 83 e5 07 and $0x7,%ebp 1d: 49 01 c4 add %rax,%r12 20: 83 c5 03 add $0x3,%ebp 23: e8 70 79 0b 00 callq 0xb7998 28: f3 90 pause * 2a: 41 0f b6 04 24 movzbl (%r12),%eax <-- trapping instruction 2f: 40 38 c5 cmp %al,%bpl 32: 7c 08 jl 0x3c 34: 84 c0 test %al,%al 36: 0f 85 33 06 00 00 jne 0x66f 3c: 8b 43 08 mov 0x8(%rbx),%eax 3f: 31 .byte 0x31