rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=8277, q=892) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294964878-4294954376), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.2 R running task 27248 10312 8139 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:1465 [inline] __hrtimer_run_queues+0x3f6/0xe60 kernel/time/hrtimer.c:1527 hrtimer_interrupt+0x326/0x9e0 kernel/time/hrtimer.c:1585 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:kfree+0x123/0x210 mm/slab.c:3823 Code: 89 ea 48 89 ee 4c 89 e7 e8 da ee ff ff f6 c7 02 74 ca e8 20 74 cf ff 48 83 3d 60 4d 59 08 00 0f 84 eb 00 00 00 48 89 df 57 9d <0f> 1f 44 00 00 5b 5d 41 5c 41 5d c3 65 8b 05 ea 4b 69 7e 83 f8 07 RSP: 0018:ffff88805ce8f8e8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000286 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: ffff8880988f5b80 R08: 0000000000400000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88813bff01c0 R13: ffffffff83b8f707 R14: fffffffffffffff5 R15: 0000000000400043 tty_free_file drivers/tty/tty_io.c:220 [inline] tty_open+0x5a7/0x990 drivers/tty/tty_io.c:2032 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: 0033:0x7fc1fae53049 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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:00007fc1f97c8168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc1faf65f60 RCX: 00007fc1fae53049 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007fc1faead08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff7d25a19f R14: 00007fc1f97c8300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10502 jiffies! g8277 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29728 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 ---------------- Code disassembly (best guess): 0: 89 ea mov %ebp,%edx 2: 48 89 ee mov %rbp,%rsi 5: 4c 89 e7 mov %r12,%rdi 8: e8 da ee ff ff callq 0xffffeee7 d: f6 c7 02 test $0x2,%bh 10: 74 ca je 0xffffffdc 12: e8 20 74 cf ff callq 0xffcf7437 17: 48 83 3d 60 4d 59 08 cmpq $0x0,0x8594d60(%rip) # 0x8594d7f 1e: 00 1f: 0f 84 eb 00 00 00 je 0x110 25: 48 89 df mov %rbx,%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 5b pop %rbx 30: 5d pop %rbp 31: 41 5c pop %r12 33: 41 5d pop %r13 35: c3 retq 36: 65 8b 05 ea 4b 69 7e mov %gs:0x7e694bea(%rip),%eax # 0x7e694c27 3d: 83 f8 07 cmp $0x7,%eax