audit: type=1400 audit(1601921389.561:8): avc:  denied  { execmem } for  pid=6499 comm="syz-executor856" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
BFS-fs: bfs_fill_super(): loop0 is unclean, continuing
==================================================================
BUG: KASAN: slab-out-of-bounds in find_first_zero_bit+0xa8/0xb0 lib/find_bit.c:125
Read of size 8 at addr ffff8880a7486e00 by task syz-executor856/6499

CPU: 0 PID: 6499 Comm: syz-executor856 Not tainted 4.19.149-syzkaller #0
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+0x22c/0x33e lib/dump_stack.c:118
 print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
 kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 find_first_zero_bit+0xa8/0xb0 lib/find_bit.c:125
 bfs_create+0xf3/0x580 fs/bfs/dir.c:91
 lookup_open+0x86c/0x19c0 fs/namei.c:3235
 do_last fs/namei.c:3327 [inline]
 path_openat+0x10d6/0x2e90 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+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444439
Code: 8d d7 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 5b d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc8a3cce38 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444439
RDX: 00000000001015c2 RSI: 0000000020000440 RDI: ffffffffffffff9c
RBP: 00000000006cf018 R08: 00007ffc00000015 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402020
R13: 00000000004020b0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6499:
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc+0x15a/0x4f0 mm/slab.c:3736
 kmalloc include/linux/slab.h:520 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 bfs_fill_super+0x447/0xfa0 fs/bfs/inode.c:363
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4706:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x250 mm/slab.c:3822
 do_delayed_call include/linux/delayed_call.h:28 [inline]
 put_link fs/namei.c:883 [inline]
 step_into fs/namei.c:1773 [inline]
 walk_component+0x204/0xda0 fs/namei.c:1830
 link_path_walk.part.0+0x541/0x1230 fs/namei.c:2139
 link_path_walk fs/namei.c:2073 [inline]
 path_openat+0x21d/0x2e90 fs/namei.c:3536
 do_filp_open+0x18c/0x3f0 fs/namei.c:3567
 do_sys_open+0x3b3/0x520 fs/open.c:1085
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a7486e00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880a7486e00, ffff8880a7486e20)
The buggy address belongs to the page:
page:ffffea00029d2180 count:1 mapcount:0 mapping:ffff88812c3f61c0 index:0xffff8880a7486fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea0002918988 ffffea0002911e08 ffff88812c3f61c0
raw: ffff8880a7486fc1 ffff8880a7486000 0000000100000025 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7486d00: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff8880a7486d80: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a7486e00: 07 fc fc fc fc fc fc fc 00 00 01 fc fc fc fc fc
                   ^
 ffff8880a7486e80: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a7486f00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================