rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10656 ticks this GP) idle=94e/1/0x4000000000000002 softirq=114821/114823 fqs=5149 rcu: (t=10500 jiffies g=180181 q=3528) NMI backtrace for cpu 0 CPU: 0 PID: 13654 Comm: syz-executor0 Not tainted 4.20.0-next-20190107 #6 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1211 print_cpu_stall.cold+0x227/0x40c kernel/rcu/tree.c:1348 check_cpu_stall kernel/rcu/tree.c:1422 [inline] rcu_pending kernel/rcu/tree.c:3018 [inline] rcu_check_callbacks+0xb32/0x1380 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+0x3a7/0x1050 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+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:766 [inline] RIP: 0010:console_unlock+0xcdb/0x1040 kernel/printk/printk.c:2463 Code: c1 e8 03 42 80 3c 30 00 0f 85 62 03 00 00 48 83 3d 09 85 2a 08 00 0f 84 97 01 00 00 e8 1e 17 1a 00 48 8b bd 18 ff ff ff 57 9d <0f> 1f 44 00 00 e9 62 ff ff ff e8 06 17 1a 00 48 8b 7d 08 c7 05 48 RSP: 0018:ffff88820f81f0d0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: 0000000000000200 RCX: ffffc90005dd3000 RDX: 0000000000040000 RSI: ffffffff8167faf2 RDI: 0000000000000246 RBP: ffff88820f81f1e0 R08: 0000000000000006 R09: ffff88804c85aad8 R10: ffff88804c85a1c0 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff849e50f0 R14: dffffc0000000000 R15: ffffffff89f7ac70 vprintk_emit+0x370/0x960 kernel/printk/printk.c:1978 vprintk_default+0x28/0x30 kernel/printk/printk.c:2005 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2038 __find_get_block_slow fs/buffer.c:235 [inline] __find_get_block fs/buffer.c:1325 [inline] __find_get_block.cold+0x81/0xfb fs/buffer.c:1319 __getblk_slow fs/buffer.c:1058 [inline] __getblk_gfp+0x3c5/0x1130 fs/buffer.c:1351 __bread_gfp+0x2f/0x300 fs/buffer.c:1385 sb_bread include/linux/buffer_head.h:307 [inline] fat__get_entry+0x586/0xa40 fs/fat/dir.c:101 fat_get_entry fs/fat/dir.c:129 [inline] fat_search_long+0x345/0x17d0 fs/fat/dir.c:479 vfat_find+0x10e/0x140 fs/fat/namei_vfat.c:697 vfat_lookup+0x10a/0x6b0 fs/fat/namei_vfat.c:711 __lookup_hash+0x122/0x190 fs/namei.c:1546 filename_create+0x1d6/0x5a0 fs/namei.c:3636 user_path_create fs/namei.c:3693 [inline] do_mknodat+0x1bd/0x530 fs/namei.c:3754 __do_sys_mknod fs/namei.c:3794 [inline] __se_sys_mknod fs/namei.c:3792 [inline] __x64_sys_mknod+0x7b/0xb0 fs/namei.c:3792 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f862e9acc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000085 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000340 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f862e9ad6d4 R13: 00000000004c3b27 R14: 00000000004d6880 R15: 00000000ffffffff