rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=607369, q=31) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295292678-4295282175), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor5 R running task 30064 27017 16585 0x0000000a Call Trace: sched_show_task kernel/sched/core.c:5306 [inline] sched_show_task.cold+0x292/0x30b kernel/sched/core.c:5281 print_other_cpu_stall kernel/rcu/tree.c:1301 [inline] check_cpu_stall kernel/rcu/tree.c:1429 [inline] rcu_pending kernel/rcu/tree.c:3018 [inline] rcu_check_callbacks.cold+0xa10/0xa4a kernel/rcu/tree.c:2521 update_process_times+0x32/0x80 kernel/time/timer.c:1635 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:__sanitizer_cov_trace_pc+0x4b/0x50 kernel/kcov.c:111 Code: 90 d8 12 00 00 83 fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 <5d> c3 0f 1f 00 65 4c 8b 04 25 40 ee 01 00 65 8b 05 c0 11 92 7e a9 RSP: 0018:ffff888050fd7c48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc90013457000 RDX: 0000000000040000 RSI: ffffffff8631d6ad RDI: ffff888093020928 RBP: ffff888050fd7c48 R08: ffff888098c5c540 R09: fffffbfff1282719 R10: fffffbfff1282718 R11: ffffffff894138c3 R12: ffff888093020928 R13: 0000000000000001 R14: ffff8880a7ca2640 R15: 0000000000000000 __x25_find_socket+0x6d/0x120 net/x25/af_x25.c:327 x25_new_lci net/x25/af_x25.c:357 [inline] x25_connect+0x374/0xdf0 net/x25/af_x25.c:786 __sys_connect+0x266/0x330 net/socket.c:1686 __do_sys_connect net/socket.c:1697 [inline] __se_sys_connect net/socket.c:1694 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1694 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e39 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f0c714e3c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e39 RDX: 0000000000000012 RSI: 0000000020000240 RDI: 0000000000000005 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0c714e46d4 R13: 00000000004be378 R14: 00000000004cea60 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10536 jiffies! g607369 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28832 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2844 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3485 schedule+0x92/0x180 kernel/sched/core.c:3529 schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803 rcu_gp_fqs_loop kernel/rcu/tree.c:1948 [inline] rcu_gp_kthread+0x956/0x17a0 kernel/rcu/tree.c:2105 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352