syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18990): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18990): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0 rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10499 ticks this GP) idle=43e/1/0x4000000000000002 softirq=38301/38301 fqs=5248 rcu: (t=10501 jiffies g=61385 q=1050) NMI backtrace for cpu 1 CPU: 1 PID: 18980 Comm: syz-executor0 Not tainted 4.20.0-rc6-next-20181214+ #171 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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+0x16f/0x1bc kernel/rcu/tree.c:1211 print_cpu_stall.cold.70+0x218/0x40a 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+0xf3b/0x13f0 kernel/rcu/tree.c:2521 update_process_times+0x2d/0x70 kernel/time/timer.c:1635 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:161 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:146 Code: 14 dd 28 00 00 00 4d 39 d0 72 1b 49 83 c1 01 4a 89 7c 10 e0 4a 89 74 10 e8 4a 89 54 10 f0 4a 89 4c d8 20 4c 89 08 5d c3 66 90 <55> 48 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 98 ea RSP: 0018:ffff8881937be688 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: 1ffff110326f7cdd RCX: ffffc90005dae000 RDX: 0000000000040000 RSI: ffffffff8880e760 RDI: ffffffff8880e7a0 RBP: ffff8881937be6c0 R08: ffff8881b8e30700 R09: ffffed103b5a5b77 R10: ffffed103b5a5b77 R11: ffff8881dad2dbbb R12: 000000000002db00 R13: ffffffff8880e7a0 R14: ffffffff8880e760 R15: dffffc0000000000 debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:56 rcu_dynticks_curr_cpu_in_eqs+0x69/0x170 kernel/rcu/tree.c:303 rcu_is_watching+0x10/0x30 kernel/rcu/tree.c:932 rcu_read_unlock include/linux/rcupdate.h:657 [inline] find_get_entry+0xd39/0x1120 mm/filemap.c:1506 pagecache_get_page+0x12f/0xf00 mm/filemap.c:1579 find_or_create_page include/linux/pagemap.h:322 [inline] grow_dev_page fs/buffer.c:947 [inline] grow_buffers fs/buffer.c:1029 [inline] __getblk_slow fs/buffer.c:1062 [inline] __getblk_gfp+0x4ca/0x1030 fs/buffer.c:1351 __bread_gfp+0x2d/0x310 fs/buffer.c:1385 sb_bread include/linux/buffer_head.h:307 [inline] fat_ent_bread+0x173/0x290 fs/fat/fatent.c:107 fat_ent_read+0x646/0xc10 fs/fat/fatent.c:368 fat_free_clusters+0x31c/0xe80 fs/fat/fatent.c:565 fat_free fs/fat/file.c:379 [inline] fat_truncate_blocks+0x983/0x10a0 fs/fat/file.c:397 fat_setattr+0xc3d/0xe20 fs/fat/file.c:541 notify_change+0xbde/0x1110 fs/attr.c:334 do_truncate+0x1bd/0x2d0 fs/open.c:63 handle_truncate fs/namei.c:3008 [inline] do_last fs/namei.c:3424 [inline] path_openat+0x375f/0x5150 fs/namei.c:3534 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x780 fs/open.c:1063 ksys_open include/linux/syscalls.h:1311 [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+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457659 Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe689874c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457659 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe6898756d4 R13: 00000000004bdd13 R14: 00000000004cd7b8 R15: 00000000ffffffff syz-executor0(18990): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18990): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18990): getblk(): executed=9 bh_count=0 bh_state=0 syz-executor0(18980): getblk(): executed=9 bh_count=0 bh_state=0