KASAN: out-of-bounds Read in leaf_paste_entries

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbfa1702 Linux 4.14.198
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17caa593900000
kernel config: https://syzkaller.appspot.com/x/.config?x=3990958d85b55e59
dashboard link: https://syzkaller.appspot.com/bug?extid=ca66b2bad4f257b51ec4
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ca66b2...@syzkaller.appspotmail.com

REISERFS (device loop4): Using rupasov hash to sort names
==================================================================
BUG: KASAN: out-of-bounds in memmove include/linux/string.h:387 [inline]
BUG: KASAN: out-of-bounds in leaf_paste_entries+0x45b/0x9b0 fs/reiserfs/lbalance.c:1378
Read of size 18446744073709551584 at addr ffff88801309efa4 by task syz-executor.4/19786

CPU: 0 PID: 19786 Comm: syz-executor.4 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+0x6f/0x7b mm/kasan/report.c:409
memmove+0x20/0x50 mm/kasan/kasan.c:293
memmove include/linux/string.h:387 [inline]
leaf_paste_entries+0x45b/0x9b0 fs/reiserfs/lbalance.c:1378
balance_leaf_finish_node_paste_dirent fs/reiserfs/do_balan.c:1306 [inline]
balance_leaf_finish_node_paste fs/reiserfs/do_balan.c:1332 [inline]
balance_leaf_finish_node fs/reiserfs/do_balan.c:1375 [inline]
balance_leaf+0x81f4/0xb830 fs/reiserfs/do_balan.c:1463
do_balance+0x27e/0x630 fs/reiserfs/do_balan.c:1899
reiserfs_paste_into_item+0x507/0x670 fs/reiserfs/stree.c:2142
reiserfs_add_entry+0x73b/0xb00 fs/reiserfs/namei.c:566
reiserfs_mkdir+0x5ca/0x8b0 fs/reiserfs/namei.c:858
create_privroot fs/reiserfs/xattr.c:873 [inline]
reiserfs_xattr_init+0x393/0xa49 fs/reiserfs/xattr.c:995
reiserfs_fill_super+0x1b10/0x28b6 fs/reiserfs/super.c:2180
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
RIP: 0033:0x46087a
RSP: 002b:00007f2d57690a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2d57690b20 RCX: 000000000046087a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f2d57690ae0
RBP: 00007f2d57690ae0 R08: 00007f2d57690b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020011200

The buggy address belongs to the page:
page:ffffea00004c2780 count:3 mapcount:0 mapping:ffff8880a696aaa8 index:0x2013
flags: 0xfffe0000001044(referenced|active|private)
raw: 00fffe0000001044 ffff8880a696aaa8 0000000000002013 00000003ffffffff
raw: dead000000000100 dead000000000200 ffff888053b9a498 ffff8880aa3f6a40
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8880aa3f6a40

Memory state around the buggy address:
ffff88801309ee80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801309ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88801309ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff88801309f000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88801309f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 87335852 Linux 4.14.209
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10c442e9500000
kernel config: https://syzkaller.appspot.com/x/.config?x=a932ed2a762225b

dashboard link: https://syzkaller.appspot.com/bug?extid=ca66b2bad4f257b51ec4
compiler: gcc (GCC) 10.1.0-syz 20200507

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1443ff1d500000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1025bd95500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ca66b2...@syzkaller.appspotmail.com

reiserfs: using flush barriers
REISERFS (device loop0): journal params: device loop0, size 8192, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using rupasov hash to sort names

==================================================================
BUG: KASAN: out-of-bounds in memmove include/linux/string.h:387 [inline]

BUG: KASAN: out-of-bounds in leaf_paste_entries+0x421/0x9b0 fs/reiserfs/lbalance.c:1369
Read of size 18446744073709551571 at addr ffff88808760efe1 by task syz-executor856/7985

CPU: 1 PID: 7985 Comm: syz-executor856 Not tainted 4.14.209-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+0x6f/0x7b mm/kasan/report.c:409
memmove+0x20/0x50 mm/kasan/kasan.c:293
memmove include/linux/string.h:387 [inline]

leaf_paste_entries+0x421/0x9b0 fs/reiserfs/lbalance.c:1369

balance_leaf_finish_node_paste_dirent fs/reiserfs/do_balan.c:1306 [inline]
balance_leaf_finish_node_paste fs/reiserfs/do_balan.c:1332 [inline]
balance_leaf_finish_node fs/reiserfs/do_balan.c:1375 [inline]

balance_leaf+0x8298/0xbaa0 fs/reiserfs/do_balan.c:1463
do_balance+0x27e/0x630 fs/reiserfs/do_balan.c:1899
reiserfs_paste_into_item+0x569/0x6f0 fs/reiserfs/stree.c:2142
reiserfs_add_entry+0x7d3/0xbc0 fs/reiserfs/namei.c:566
reiserfs_mkdir+0x5ca/0x8b0 fs/reiserfs/namei.c:858
create_privroot fs/reiserfs/xattr.c:880 [inline]
reiserfs_xattr_init+0x393/0xa49 fs/reiserfs/xattr.c:1002
reiserfs_fill_super+0x1b18/0x28be fs/reiserfs/super.c:2180

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

RIP: 0033:0x4470da
RSP: 002b:00007fff9e730218 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff9e730270 RCX: 00000000004470da
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff9e730230
RBP: 00007fff9e730230 R08: 00007fff9e730270 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000007
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

The buggy address belongs to the page:

page:ffffea00021d8380 count:3 mapcount:0 mapping:ffff8880b1fd1568 index:0x2013
flags: 0xfff00000001044(referenced|active|private)
raw: 00fff00000001044 ffff8880b1fd1568 0000000000002013 00000003ffffffff
raw: dead000000000100 dead000000000200 ffff88808845eb28 ffff88823b3201c0

page dumped because: kasan: bad access detected

page->mem_cgroup:ffff88823b3201c0

Memory state around the buggy address:

ffff88808760ee80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88808760ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808760ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff88808760f000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88808760f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================