[syzbot] [ocfs2?] KASAN: use-after-free Read in ocfs2_search_extent_list

syzbot
2024-12-09T23:04:24Z

Hello,

syzbot found the following issue on:

HEAD commit: 5076001689e4 Merge tag 'loongarch-fixes-6.13-1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=120f68df980000
kernel config: https://syzkaller.appspot.com/x/.config?x=50c7a61469ce77e7
dashboard link: https://syzkaller.appspot.com/bug?extid=2313dda4dc4885c93578
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b29330580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17b29330580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-50760016.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/76ef343a98c8/vmlinux-50760016.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e42b3235bcc3/bzImage-50760016.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/893e4e85ff3d/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2313dda4dc4885c93578@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
JBD2: Ignoring recovery information on journal
==================================================================
BUG: KASAN: use-after-free in ocfs2_search_extent_list+0x155/0x200 fs/ocfs2/alloc.c:776
Read of size 4 at addr ffff888049800000 by task syz-executor307/5410

CPU: 0 UID: 0 PID: 5410 Comm: syz-executor307 Not tainted 6.13.0-rc1-syzkaller-00036-g5076001689e4 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
ocfs2_search_extent_list+0x155/0x200 fs/ocfs2/alloc.c:776
ocfs2_get_clusters_nocache+0x21a/0xbf0 fs/ocfs2/extent_map.c:438
ocfs2_get_clusters+0x5bd/0xbd0 fs/ocfs2/extent_map.c:621
ocfs2_extent_map_get_blocks+0x24c/0x7d0 fs/ocfs2/extent_map.c:668
ocfs2_bmap+0x2b7/0x780 fs/ocfs2/aops.c:474
bmap+0xa8/0xe0 fs/inode.c:1997
jbd2_journal_bmap+0x12d/0x2b0 fs/jbd2/journal.c:926
do_readahead fs/jbd2/recovery.c:88 [inline]
jread+0x435/0xc80 fs/jbd2/recovery.c:165
do_one_pass+0x3cd/0x3aa0 fs/jbd2/recovery.c:646
jbd2_journal_skip_recovery+0x95/0x240 fs/jbd2/recovery.c:366
jbd2_journal_wipe+0xc9/0x110 fs/jbd2/journal.c:2517
ocfs2_journal_wipe+0xab/0x2a0 fs/ocfs2/journal.c:1192
ocfs2_check_volume fs/ocfs2/super.c:2413 [inline]
ocfs2_mount_volume+0xb86/0x1940 fs/ocfs2/super.c:1817
ocfs2_fill_super+0x476e/0x5760 fs/ocfs2/super.c:1084
mount_bdev+0x20a/0x2d0 fs/super.c:1693
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdc66ec71aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffee9a2de18 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffee9a2de30 RCX: 00007fdc66ec71aa
RDX: 0000000020004440 RSI: 0000000020000040 RDI: 00007ffee9a2de30
RBP: 0000000000000004 R08: 00007ffee9a2de70 R09: 0000000000004431
R10: 00000000000008c0 R11: 0000000000000282 R12: 00000000000008c0
R13: 00007ffee9a2de70 R14: 0000000000000003 R15: 0000000001000000
</TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x49800
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 04fff00000000000 ffff88805ffd7230 ffff88805ffd7230 0000000000000000
raw: 0000000000000000 000000000000000a 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
ffff8880497fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880497fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888049800000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888049800080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888049800100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

---
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