rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (5593 ticks this GP) idle=8be/1/0x4000000000000002 softirq=39396/39396 fqs=4244 rcu: (t=10500 jiffies g=51465 q=600) NMI backtrace for cpu 0 CPU: 0 PID: 17364 Comm: syz-executor0 Not tainted 4.20.0-next-20190103 #5 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:__find_get_block+0x31b/0xf20 fs/buffer.c:1323 Code: ff df 48 c1 ea 03 80 3c 02 00 0f 85 bc 0a 00 00 48 83 3d d7 1c af 07 00 0f 84 f6 08 00 00 e8 cc 9d 9e ff fb 66 0f 1f 44 00 00 <4d> 85 ff 0f 84 31 02 00 00 e8 b7 9d 9e ff 0f 1f 44 00 00 e8 ad 9d RSP: 0018:ffff888056d26f50 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffff888089447bd0 RCX: ffffc90005db9000 RDX: 0000000000040000 RSI: ffffffff81e36334 RDI: ffff8880550a2f3c RBP: ffff888056d27078 R08: 0000000000000006 R09: ffff8880550a2fd8 R10: ffff8880550a26c0 R11: 0000000000000000 R12: 0000000000000010 R13: 0000000000000006 R14: dffffc0000000000 R15: 0000000000000000 __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_ent_bread+0x16c/0x290 fs/fat/fatent.c:107 fat_ent_read+0x646/0xc30 fs/fat/fatent.c:366 fat_free_clusters+0x31c/0xeb0 fs/fat/fatent.c:563 fat_free fs/fat/file.c:379 [inline] fat_truncate_blocks+0x9a1/0x1160 fs/fat/file.c:397 fat_setattr+0xc3c/0xe20 fs/fat/file.c:541 notify_change+0xb8d/0x1080 fs/attr.c:334 do_truncate+0x1ba/0x2d0 fs/open.c:63 handle_truncate fs/namei.c:3008 [inline] do_last fs/namei.c:3424 [inline] path_openat+0x3812/0x5660 fs/namei.c:3534 do_filp_open+0x26f/0x370 fs/namei.c:3564 do_sys_open+0x59a/0x7c0 fs/open.c:1063 ksys_open include/linux/syscalls.h:1298 [inline] __do_sys_creat fs/open.c:1121 [inline] __se_sys_creat fs/open.c:1119 [inline] __x64_sys_creat+0x61/0x80 fs/open.c:1119 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:00007faf2ad8bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007faf2ad8c6d4 R13: 00000000004be42a R14: 00000000004ce8b8 R15: 00000000ffffffff