random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KASAN: use-after-free in take_option security/selinux/hooks.c:2619 [inline]
BUG: KASAN: use-after-free in selinux_sb_copy_data+0x1cd/0x380 security/selinux/hooks.c:2674
Write of size 10 at addr ffff8801c3210000 by task syz-executor782/3804

CPU: 1 PID: 3804 Comm: syz-executor782 Not tainted 4.9.122-g54068d6 #30
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801b6f0f490 ffffffff81eb8829 ffffea00070c8400 ffff8801c3210000
 0000000000000001 ffff8801c3210000 000000000000000a ffff8801b6f0f4c8
 ffffffff8156b6be ffff8801c3210000 000000000000000a 0000000000000001
Call Trace:
 [<ffffffff81eb8829>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb8829>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8156b6be>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff8156bac8>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff8156bac8>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff8153e16f>] check_memory_region_inline mm/kasan/kasan.c:318 [inline]
 [<ffffffff8153e16f>] check_memory_region+0x14f/0x1b0 mm/kasan/kasan.c:325
 [<ffffffff8153e7c7>] memcpy+0x37/0x50 mm/kasan/kasan.c:361
 [<ffffffff81d0d8ed>] take_option security/selinux/hooks.c:2619 [inline]
 [<ffffffff81d0d8ed>] selinux_sb_copy_data+0x1cd/0x380 security/selinux/hooks.c:2674
 [<ffffffff81cef45b>] security_sb_copy_data+0x7b/0xb0 security/security.c:283
 [<ffffffff8197fa86>] parse_security_options+0x36/0x90 fs/btrfs/super.c:1493
 [<ffffffff81990ab3>] btrfs_mount+0x2f3/0x2bc0 fs/btrfs/super.c:1572
 [<ffffffff81581d9c>] mount_fs+0x28c/0x370 fs/super.c:1206
 [<ffffffff815e1681>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:1000
 [<ffffffff815e19c0>] vfs_kern_mount+0x40/0x60 fs/namespace.c:982
 [<ffffffff81990bcb>] mount_subvol fs/btrfs/super.c:1395 [inline]
 [<ffffffff81990bcb>] btrfs_mount+0x40b/0x2bc0 fs/btrfs/super.c:1566
 [<ffffffff81581d9c>] mount_fs+0x28c/0x370 fs/super.c:1206
 [<ffffffff815e1681>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:1000
 [<ffffffff815e8ea9>] vfs_kern_mount fs/namespace.c:982 [inline]
 [<ffffffff815e8ea9>] do_new_mount fs/namespace.c:2537 [inline]
 [<ffffffff815e8ea9>] do_mount+0x3c9/0x2740 fs/namespace.c:2859
 [<ffffffff8168fc8c>] C_SYSC_mount fs/compat.c:810 [inline]
 [<ffffffff8168fc8c>] compat_SyS_mount+0x4fc/0xff0 fs/compat.c:775
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff83a023d0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

The buggy address belongs to the page:
page:ffffea00070c8400 count:0 mapcount:-127 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c320ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c320ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c3210000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8801c3210080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801c3210100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================