rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=29633, q=74) rcu: All QSes seen, last rcu_preempt kthread activity 10501 (4294986591-4294976090), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.5 R running task 25816 13421 10448 0x00004000 Call Trace: <IRQ> sched_show_task kernel/sched/core.c:5954 [inline] sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5929 print_other_cpu_stall kernel/rcu/tree_stall.h:430 [inline] check_cpu_stall kernel/rcu/tree_stall.h:558 [inline] rcu_pending kernel/rcu/tree.c:3030 [inline] rcu_sched_clock_irq.cold+0xb23/0xc37 kernel/rcu/tree.c:2276 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 </IRQ> RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:43 [inline] RIP: 0010:update_stack_state+0x133/0x5f0 arch/x86/kernel/unwind_frame.c:224 Code: 08 84 c0 0f 85 a9 04 00 00 41 c6 45 35 01 4c 89 a5 60 ff ff ff 48 c7 85 70 ff ff ff a8 00 00 00 49 8d 55 08 8b 85 5c ff ff ff <49> bf 00 00 00 00 00 fc ff df 49 89 d4 48 89 95 48 ff ff ff 49 c1 RSP: 0018:ffffc900076f7400 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: ffffc900076f7518 RCX: 1ffff92000edeeac RDX: ffffc900076f7530 RSI: ffffc900076f7518 RDI: ffffc900076f7560 RBP: ffffc900076f74c8 R08: ffffc900076f7550 R09: ffffc900076f7528 R10: fffff52000edeeb0 R11: ffffc900076f7587 R12: 0000000000000000 R13: ffffc900076f7528 R14: 1ffff92000edee88 R15: ffffc900076f7528 __unwind_start+0x189/0x3d0 arch/x86/kernel/unwind_frame.c:400 unwind_start arch/x86/include/asm/unwind.h:60 [inline] arch_stack_walk+0x5e/0xf0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8f/0xc0 kernel/stacktrace.c:123 save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x163/0x770 mm/slab.c:3665 kmalloc_array include/linux/slab.h:597 [inline] kcalloc include/linux/slab.h:608 [inline] iter_file_splice_write+0x16e/0xc10 fs/splice.c:702 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1037 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:992 do_splice_direct+0x1da/0x2a0 fs/splice.c:1080 do_sendfile+0x597/0xd00 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1575 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1567 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa3b044fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fa3b04506d4 RCX: 000000000045b399 RDX: 00000000200001c0 RSI: 0000000000000008 RDI: 0000000000000008 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008cb R14: 00000000004ca259 R15: 000000000075bf2c rcu: rcu_preempt kthread starved for 10559 jiffies! g29633 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29264 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4082 schedule+0xdc/0x2b0 kernel/sched/core.c:4156 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline] rcu_gp_kthread+0xa10/0x1940 kernel/rcu/tree.c:1818 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352