rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=677/1/0x4000000000000000 softirq=7727/7727 fqs=0 (t=10500 jiffies g=7493 q=274) rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g7493 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=9415 rcu: rcu_preempt kthread starved for 10500 jiffies! g7493 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:25720 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0x971/0x10e0 kernel/sched/core.c:6296 schedule+0x12b/0x1f0 kernel/sched/core.c:6369 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1963 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2136 kthread+0x2a3/0x2d0 kernel/kthread.c:359 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 4154 Comm: syz-executor.4 Not tainted 5.16.0-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+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:458 print_cpu_stall kernel/rcu/tree_stall.h:602 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3919 [inline] rcu_sched_clock_irq+0x1e2e/0x2bc0 kernel/rcu/tree.c:2617 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1428 __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:__block_commit_write+0x2f1/0x330 fs/buffer.c:2101 Code: e6 01 31 ff e8 30 09 98 ff 48 83 e3 01 75 43 e8 75 04 98 ff 48 89 ef be 08 00 00 00 e8 d8 96 e3 ff f0 80 4d 00 04 48 83 c4 28 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 e8 4f 04 98 ff 4c 89 f7 48 c7 c6 RSP: 0018:ffffc9000b3f7188 EFLAGS: 00000286 RAX: ffffffff81ed9b01 RBX: 0000000000000000 RCX: ffffffff81ed9bd8 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffea0000f61180 RBP: ffffea0000f61180 R08: dffffc0000000000 R09: fffff940001ec231 R10: fffff940001ec231 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000001000 block_write_end+0x43/0x170 fs/buffer.c:2163 generic_write_end+0x8d/0x170 fs/buffer.c:2177 ext4_da_write_end+0x7bb/0x870 fs/ext4/inode.c:3042 generic_perform_write+0x3da/0x600 mm/filemap.c:3698 ext4_buffered_write_iter+0x3b5/0x580 fs/ext4/file.c:268 ext4_file_write_iter+0x8f7/0x1bb0 do_iter_readv_writev+0x54f/0x740 do_iter_write+0x21e/0x7b0 fs/read_write.c:851 iter_file_splice_write+0x7eb/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe6/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x529/0xd00 fs/splice.c:891 do_splice_direct+0x291/0x3e0 fs/splice.c:979 do_sendfile+0x6fe/0x1040 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64+0x171/0x1d0 fs/read_write.c:1296 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: 0033:0x7fe7336abfe9 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:00007fe732021168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe7337bef60 RCX: 00007fe7336abfe9 RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000006 RBP: 00007fe73370608d R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdaeee851f R14: 00007fe732021300 R15: 0000000000022000 NMI backtrace for cpu 1 CPU: 1 PID: 4154 Comm: syz-executor.4 Not tainted 5.16.0-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+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3919 [inline] rcu_sched_clock_irq+0x1e33/0x2bc0 kernel/rcu/tree.c:2617 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1428 __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:__block_commit_write+0x2f1/0x330 fs/buffer.c:2101 Code: e6 01 31 ff e8 30 09 98 ff 48 83 e3 01 75 43 e8 75 04 98 ff 48 89 ef be 08 00 00 00 e8 d8 96 e3 ff f0 80 4d 00 04 48 83 c4 28 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 e8 4f 04 98 ff 4c 89 f7 48 c7 c6 RSP: 0018:ffffc9000b3f7188 EFLAGS: 00000286 RAX: ffffffff81ed9b01 RBX: 0000000000000000 RCX: ffffffff81ed9bd8 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffea0000f61180 RBP: ffffea0000f61180 R08: dffffc0000000000 R09: fffff940001ec231 R10: fffff940001ec231 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000001000 block_write_end+0x43/0x170 fs/buffer.c:2163 generic_write_end+0x8d/0x170 fs/buffer.c:2177 ext4_da_write_end+0x7bb/0x870 fs/ext4/inode.c:3042 generic_perform_write+0x3da/0x600 mm/filemap.c:3698 ext4_buffered_write_iter+0x3b5/0x580 fs/ext4/file.c:268 ext4_file_write_iter+0x8f7/0x1bb0 do_iter_readv_writev+0x54f/0x740 do_iter_write+0x21e/0x7b0 fs/read_write.c:851 iter_file_splice_write+0x7eb/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe6/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x529/0xd00 fs/splice.c:891 do_splice_direct+0x291/0x3e0 fs/splice.c:979 do_sendfile+0x6fe/0x1040 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64+0x171/0x1d0 fs/read_write.c:1296 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: 0033:0x7fe7336abfe9 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:00007fe732021168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe7337bef60 RCX: 00007fe7336abfe9 RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000006 RBP: 00007fe73370608d R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdaeee851f R14: 00007fe732021300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: e6 01 out %al,$0x1 2: 31 ff xor %edi,%edi 4: e8 30 09 98 ff callq 0xff980939 9: 48 83 e3 01 and $0x1,%rbx d: 75 43 jne 0x52 f: e8 75 04 98 ff callq 0xff980489 14: 48 89 ef mov %rbp,%rdi 17: be 08 00 00 00 mov $0x8,%esi 1c: e8 d8 96 e3 ff callq 0xffe396f9 21: f0 80 4d 00 04 lock orb $0x4,0x0(%rbp) 26: 48 83 c4 28 add $0x28,%rsp * 2a: 5b pop %rbx <-- trapping instruction 2b: 41 5c pop %r12 2d: 41 5d pop %r13 2f: 41 5e pop %r14 31: 41 5f pop %r15 33: 5d pop %rbp 34: c3 retq 35: e8 4f 04 98 ff callq 0xff980489 3a: 4c 89 f7 mov %r14,%rdi 3d: 48 rex.W 3e: c7 .byte 0xc7 3f: c6 .byte 0xc6