audit: type=1400 audit(1600643209.905:8): avc:  denied  { execmem } for  pid=6392 comm="syz-executor134" 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+0x84/0x90 lib/find_bit.c:105
Read of size 8 at addr ffff88809f39a740 by task syz-executor134/6392

CPU: 1 PID: 6392 Comm: syz-executor134 Not tainted 4.14.198-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 find_first_zero_bit+0x84/0x90 lib/find_bit.c:105
 bfs_create+0xfb/0x620 fs/bfs/dir.c:92
 lookup_open+0x77a/0x1750 fs/namei.c:3241
 do_last fs/namei.c:3334 [inline]
 path_openat+0xe08/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x444449
RSP: 002b:00007fffa3839f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444449
RDX: 00000000001015c2 RSI: 0000000020000440 RDI: ffffffffffffff9c
RBP: 00000000006cf018 R08: 00007fff00000015 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402030
R13: 00000000004020c0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6392:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 bfs_fill_super+0x3d5/0xd80 fs/bfs/inode.c:363
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 4534:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 proc_pid_attr_write+0x1fe/0x280 fs/proc/base.c:2593
 __vfs_write+0xe4/0x630 fs/read_write.c:480
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88809f39a740
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff88809f39a740, ffff88809f39a760)
The buggy address belongs to the page:
page:ffffea00027ce680 count:1 mapcount:0 mapping:ffff88809f39a000 index:0xffff88809f39afc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809f39a000 ffff88809f39afc1 000000010000001d
raw: ffffea0002640960 ffffea00023d3fe0 ffff88812fe501c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f39a600: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809f39a680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88809f39a700: fb fb fb fb fc fc fc fc 07 fc fc fc fc fc fc fc
                                           ^
 ffff88809f39a780: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff88809f39a800: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================