rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=5245, q=53) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294998001-4294987498), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor554 R running task 26984 8175 8095 0x00000000 Call Trace: sched_show_task.cold+0x332/0x396 kernel/sched/core.c:5337 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline] check_cpu_stall kernel/rcu/tree.c:1557 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold+0xb37/0xe19 kernel/rcu/tree.c:2682 update_process_times+0x2a/0x70 kernel/time/timer.c:1650 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168 tick_sched_timer+0xfc/0x290 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1419 [inline] __hrtimer_run_queues+0x3f6/0xe60 kernel/time/hrtimer.c:1481 hrtimer_interrupt+0x326/0x9e0 kernel/time/hrtimer.c:1539 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline] smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1096 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x50 kernel/kcov.c:100 Code: e8 c1 c1 35 00 e9 ab fe ff ff 4c 89 ef e8 b4 c1 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 34 24 <65> 48 8b 04 25 80 df 01 00 65 8b 15 7c 84 9f 7e 81 e2 00 01 1f 00 RSP: 0018:ffff888094cb7858 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff8880b0144680 RBX: ffffffff8a45d1e0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8375be65 RDI: ffffffff88b3c180 RBP: ffffffff88b3c180 R08: 00000000006000c0 R09: 0000000000000003 R10: 00000000b0f57453 R11: 000000001c8f048c R12: ffff8880a296ce00 R13: ffffffff88b3c140 R14: 0000000000000020 R15: ffffffff83b78d78 check_preemption_disabled+0x15/0x280 lib/smp_processor_id.c:13 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:348 [inline] rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:1025 rcu_read_lock_sched_held+0xc6/0x1d0 kernel/rcu/update.c:113 trace_kmalloc include/trace/events/kmem.h:46 [inline] kmem_cache_alloc_trace+0x323/0x380 mm/slab.c:3626 kmalloc include/linux/slab.h:515 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x138/0x990 drivers/tty/tty_io.c:2023 chrdev_open+0x266/0x770 fs/char_dev.c:423 do_dentry_open+0x4aa/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x445a39 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2430ff3308 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445a39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c R13: 000000000049a074 R14: 7974742f7665642f R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10540 jiffies! g5245 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29208 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x4cf/0xfe0 kernel/time/timer.c:1818 rcu_gp_kthread+0xdad/0x21c0 kernel/rcu/tree.c:2202 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415