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BUG: KASAN: slab-out-of-bounds in find_first_zero_bit+0xa8/0xb0 lib/find_bit.c:125
Read of size 8 at addr ffff8880aa37acc0 by task syz-executor.1/8747

CPU: 1 PID: 8747 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 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+0xfb/0x610 fs/bfs/dir.c:91
 lookup_open+0x893/0x1a20 fs/namei.c:3235
 do_last fs/namei.c:3327 [inline]
 path_openat+0x1094/0x2df0 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+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2e759df0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2e73f51168 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f2e75afef80 RCX: 00007f2e759df0f9
RDX: 0000000000000000 RSI: 000000000014da42 RDI: 00000000200000c0
RBP: 00007f2e75a3aae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe0f326eef R14: 00007f2e73f51300 R15: 0000000000022000

Allocated by task 8747:
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc+0x15a/0x3c0 mm/slab.c:3736
 kmalloc include/linux/slab.h:520 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 bfs_fill_super+0x447/0xec0 fs/bfs/inode.c:363
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x310 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:2492 [inline]
 do_mount+0x115c/0x2f50 fs/namespace.c:2822
 ksys_mount+0xcf/0x130 fs/namespace.c:3038
 __do_sys_mount fs/namespace.c:3052 [inline]
 __se_sys_mount fs/namespace.c:3049 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3049
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4700:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 kernfs_fop_write+0x188/0x470 fs/kernfs/file.c:330
 __vfs_write+0xf7/0x770 fs/read_write.c:485
 vfs_write+0x1f3/0x540 fs/read_write.c:549
 ksys_write+0x12b/0x2a0 fs/read_write.c:599
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880aa37acc0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880aa37acc0, ffff8880aa37ace0)
The buggy address belongs to the page:
page:ffffea0002a8de80 count:1 mapcount:0 mapping:ffff88813bff01c0 index:0xffff8880aa37afc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea00017339c8 ffffea0002860e48 ffff88813bff01c0
raw: ffff8880aa37afc1 ffff8880aa37a000 000000010000003d 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880aa37ab80: 00 04 fc fc fc fc fc fc 00 04 fc fc fc fc fc fc
 ffff8880aa37ac00: 00 04 fc fc fc fc fc fc 00 04 fc fc fc fc fc fc
>ffff8880aa37ac80: 00 04 fc fc fc fc fc fc 07 fc fc fc fc fc fc fc
                                           ^
 ffff8880aa37ad00: 00 fc fc fc fc fc fc fc 00 07 fc fc fc fc fc fc
 ffff8880aa37ad80: 00 fc fc fc fc fc fc fc 00 01 fc fc fc fc fc fc
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