rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=65777, q=127) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295008611-4294998109), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.5 R running task 26584 20004 7707 0x00004000 Call Trace: sched_show_task kernel/sched/core.c:5961 [inline] sched_show_task.cold+0x2e2/0x343 kernel/sched/core.c:5936 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:3225 [inline] rcu_sched_clock_irq.cold+0xb9b/0xd00 kernel/rcu/tree.c:2296 update_process_times+0x25/0x60 kernel/time/timer.c:1727 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x5ca/0xed0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline] smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:unwind_next_frame+0x5ff/0x19d0 arch/x86/kernel/unwind_orc.c:408 Code: 7e 00 4c 8b 44 24 30 48 8b 74 24 28 48 8b 44 24 20 48 8b 4c 24 18 8b 90 a0 02 00 00 4c 89 c7 e8 f7 f2 ff ff 49 89 c0 4d 85 c0 <0f> 85 92 fd ff ff e9 56 fd ff ff 48 b8 00 00 00 00 00 fc ff df 48 RSP: 0018:ffffc900166272c0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: ffffffff8af2cd84 RBX: 1ffff92002cc4e60 RCX: ffffffff81327f32 RDX: ffffffff81327ace RSI: ffffffff8af2cd84 RDI: ffffffff8a98624c RBP: 0000000000000001 R08: ffffffff8af2cd84 R09: ffffffff8af2cd8a R10: 000000000000cb9c R11: 000000000007001f R12: ffffc90016627498 R13: ffffc90016627485 R14: ffffc900166274a0 R15: ffffc90016627450 __unwind_start arch/x86/kernel/unwind_orc.c:655 [inline] __unwind_start+0x474/0x820 arch/x86/kernel/unwind_orc.c:585 unwind_start arch/x86/include/asm/unwind.h:60 [inline] arch_stack_walk+0x57/0xd0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468 slab_post_alloc_hook mm/slab.h:586 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc_trace+0x13d/0x7d0 mm/slab.c:3549 kmalloc include/linux/slab.h:555 [inline] tty_alloc_file drivers/tty/tty_io.c:189 [inline] tty_open+0x13e/0xb40 drivers/tty/tty_io.c:2025 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 do_dentry_open+0x4b6/0x12a0 fs/open.c:797 do_open fs/namei.c:3229 [inline] path_openat+0x1e70/0x27f0 fs/namei.c:3346 do_filp_open+0x192/0x260 fs/namei.c:3373 do_sys_openat2+0x585/0x7d0 fs/open.c:1148 do_sys_open+0xc3/0x140 fs/open.c:1164 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 0d 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4395e00c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004f8b60 RCX: 000000000045c829 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000007fe R14: 00000000004cabb1 R15: 00007f4395e016d4 rcu: rcu_preempt kthread starved for 10502 jiffies! g65777 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28848 10 2 0x80004000 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4163 schedule_timeout+0x35c/0x850 kernel/time/timer.c:1898 rcu_gp_fqs_loop kernel/rcu/tree.c:1674 [inline] rcu_gp_kthread+0x9bf/0x1960 kernel/rcu/tree.c:1836 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352