rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=77849, q=5) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295004520-4294994017), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.2 R running task 26008 20342 8840 0x00004002 Call Trace: sched_show_task kernel/sched/core.c:5285 [inline] sched_show_task.cold+0x291/0x2fc kernel/sched/core.c:5260 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:536 [inline] rcu_pending kernel/rcu/tree.c:2625 [inline] rcu_sched_clock_irq.cold+0xaaf/0xbfd kernel/rcu/tree.c:2161 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x33b/0xdd0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] RIP: 0010:slab_alloc mm/slab.c:3313 [inline] RIP: 0010:__do_kmalloc mm/slab.c:3652 [inline] RIP: 0010:__kmalloc+0x2b1/0x740 mm/slab.c:3663 Code: 7e 0f 85 d6 fe ff ff e8 3e fd 56 ff e9 cc fe ff ff e8 73 f1 cc ff 48 83 3d db 11 29 07 00 0f 84 09 03 00 00 48 8b 7d c0 57 9d <0f> 1f 44 00 00 e9 65 fe ff ff 31 d2 be a9 01 00 00 48 c7 c7 6e 00 RSP: 0018:ffff8880a49078c0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000dc0 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffff88809b656ad0 RDI: 0000000000000286 RBP: ffff8880a4907938 R08: ffff88809b656ad0 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88809b656af0 R12: 0000000000000100 R13: 0000000000000dc0 R14: ffff8880aa4007c0 R15: ffff88809124b280 kmalloc_array include/linux/slab.h:670 [inline] kcalloc include/linux/slab.h:681 [inline] iter_file_splice_write+0x16e/0xbd0 fs/splice.c:690 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1020 splice_direct_to_actor+0x366/0x970 fs/splice.c:975 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe0371e0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008000fffffffe R11: 0000000000000246 R12: 00007fe0371e16d4 R13: 00000000004c6835 R14: 00000000004db7a8 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10544 jiffies! g77849 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29224 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:2818 [inline] __schedule+0x7c5/0x1560 kernel/sched/core.c:3444 schedule+0xa8/0x260 kernel/sched/core.c:3508 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline] rcu_gp_kthread+0x9b2/0x18b0 kernel/rcu/tree.c:1746 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352