FAT-fs (loop4): Directory bread(block 10) failed
FAT-fs (loop4): Directory bread(block 11) failed
FAT-fs (loop4): Directory bread(block 12) failed
FAT-fs (loop4): Directory bread(block 13) failed
==================================================================
BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: null-ptr-deref in refcount_inc_not_zero+0x8f/0x2d0 lib/refcount.c:120
Read of size 4 at addr 0000000000000004 by task syz-executor3/20904
FAT-fs (loop4): Directory bread(block 14) failed

CPU: 0 PID: 20904 Comm: syz-executor3 Not tainted 4.17.0-rc1+ #10
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+0x1b9/0x294 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.7+0x6d/0x2fe mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_inc_not_zero+0x8f/0x2d0 lib/refcount.c:120
 refcount_inc+0x15/0x70 lib/refcount.c:153
 llc_sap_hold include/net/llc.h:116 [inline]
 llc_ui_release+0xba/0x2b0 net/llc/af_llc.c:207
 sock_release+0x96/0x1b0 net/socket.c:594
 sock_close+0x16/0x20 net/socket.c:1149
 __fput+0x34d/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x2bd/0x310 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455389
RSP: 002b:00007f2e9a304c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000124
RAX: 0000000000000015 RBX: 00007f2e9a3056d4 RCX: 0000000000455389
RDX: 0000000000080000 RSI: 0000000000000015 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000006d R14: 00000000006f3ad8 R15: 0000000000000000
==================================================================