rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=e1d/1/0x4000000000000000 softirq=84176/84176 fqs=0 (t=10501 jiffies g=140425 q=91) rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g140425 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=54717 rcu: rcu_preempt kthread starved for 10504 jiffies! g140425 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28352 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: 21541 Comm: syz-executor.1 Not tainted 5.16.0-rc6-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_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x98/0x746 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: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+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:filemap_read+0x654/0xeb0 mm/filemap.c:2699 Code: 24 60 48 89 de 4c 89 ef 48 8b 44 24 28 48 21 ce 48 29 c8 48 29 f5 48 8b 4c 24 18 48 39 e8 48 0f 4e e8 48 89 ea e8 fc 79 3d 02 <48> 01 44 24 50 48 89 c3 48 8b 44 24 08 80 38 00 0f 85 50 07 00 00 RSP: 0018:ffffc900048377c8 EFLAGS: 00000286 RAX: 0000000000000a01 RBX: 0000000000000fff RCX: ffffc9000329c000 RDX: 0000000000040000 RSI: ffffffff83da15a4 RDI: 0000000000000003 RBP: 0000000000000a01 R08: 0000000000000000 R09: ffffea00020fd837 R10: ffffffff83da1b36 R11: 0000000000000000 R12: 0000000000000000 R13: ffffea00020fd800 R14: 0000000000000004 R15: dffffc0000000000 generic_file_read_iter+0x3b6/0x5a0 mm/filemap.c:2792 ext4_file_read_iter+0x1d4/0x5d0 fs/ext4/file.c:130 call_read_iter include/linux/fs.h:2156 [inline] generic_file_splice_read+0x453/0x6d0 fs/splice.c:311 do_splice_to+0x1bf/0x250 fs/splice.c:796 splice_direct_to_actor+0x2c2/0x8c0 fs/splice.c:870 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: 0033:0x7fdfc4185e99 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:00007fdfc2afb168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fdfc4298f60 RCX: 00007fdfc4185e99 RDX: 0000000000000000 RSI: 000000000000000f RDI: 0000000000000006 RBP: 00007fdfc41dfff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffea41065df R14: 00007fdfc2afb300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 21541 Comm: syz-executor.1 Not tainted 5.16.0-rc6-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: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+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:filemap_read+0x654/0xeb0 mm/filemap.c:2699 Code: 24 60 48 89 de 4c 89 ef 48 8b 44 24 28 48 21 ce 48 29 c8 48 29 f5 48 8b 4c 24 18 48 39 e8 48 0f 4e e8 48 89 ea e8 fc 79 3d 02 <48> 01 44 24 50 48 89 c3 48 8b 44 24 08 80 38 00 0f 85 50 07 00 00 RSP: 0018:ffffc900048377c8 EFLAGS: 00000286 RAX: 0000000000000a01 RBX: 0000000000000fff RCX: ffffc9000329c000 RDX: 0000000000040000 RSI: ffffffff83da15a4 RDI: 0000000000000003 RBP: 0000000000000a01 R08: 0000000000000000 R09: ffffea00020fd837 R10: ffffffff83da1b36 R11: 0000000000000000 R12: 0000000000000000 R13: ffffea00020fd800 R14: 0000000000000004 R15: dffffc0000000000 generic_file_read_iter+0x3b6/0x5a0 mm/filemap.c:2792 ext4_file_read_iter+0x1d4/0x5d0 fs/ext4/file.c:130 call_read_iter include/linux/fs.h:2156 [inline] generic_file_splice_read+0x453/0x6d0 fs/splice.c:311 do_splice_to+0x1bf/0x250 fs/splice.c:796 splice_direct_to_actor+0x2c2/0x8c0 fs/splice.c:870 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: 0033:0x7fdfc4185e99 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:00007fdfc2afb168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fdfc4298f60 RCX: 00007fdfc4185e99 RDX: 0000000000000000 RSI: 000000000000000f RDI: 0000000000000006 RBP: 00007fdfc41dfff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffea41065df R14: 00007fdfc2afb300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 24 60 and $0x60,%al 2: 48 89 de mov %rbx,%rsi 5: 4c 89 ef mov %r13,%rdi 8: 48 8b 44 24 28 mov 0x28(%rsp),%rax d: 48 21 ce and %rcx,%rsi 10: 48 29 c8 sub %rcx,%rax 13: 48 29 f5 sub %rsi,%rbp 16: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx 1b: 48 39 e8 cmp %rbp,%rax 1e: 48 0f 4e e8 cmovle %rax,%rbp 22: 48 89 ea mov %rbp,%rdx 25: e8 fc 79 3d 02 callq 0x23d7a26 * 2a: 48 01 44 24 50 add %rax,0x50(%rsp) <-- trapping instruction 2f: 48 89 c3 mov %rax,%rbx 32: 48 8b 44 24 08 mov 0x8(%rsp),%rax 37: 80 38 00 cmpb $0x0,(%rax) 3a: 0f 85 50 07 00 00 jne 0x790