[moderation] [ocfs2?] KASAN: use-after-free Write in ocfs2_write_end_nolock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: be762d8b6dd7 Merge tag 'hwmon-for-v7.0-rc6' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=158a5cba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d46eab0cfd31c214
dashboard link: https://syzkaller.appspot.com/bug?extid=a5706c40272f680ce461
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [jl...@evilplan.org jose...@linux.alibaba.com linux-...@vger.kernel.org ma...@fasheh.com ocfs2...@lists.linux.dev]

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-be762d8b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/24081999a5e6/vmlinux-be762d8b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bfe821885790/bzImage-be762d8b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a5706c...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
=======================================================
WARNING: The mand mount option has been deprecated and
and is ignored by this kernel. Remove the mand
option from the mount to silence this warning.
=======================================================
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
(syz.0.0,5326,0):ocfs2_check_set_options:1244 ERROR: Invalid heartbeat mount options
OCFS2: ERROR (device loop0): int ocfs2_validate_inode_block(struct super_block *, struct buffer_head *): Invalid dinode #17058: signature = �7�J
On-disk corruption discovered. Please run fsck.ocfs2 once the filesystem is unmounted.
OCFS2: File system is now read-only.
(syz.0.0,5326,0):ocfs2_assign_bh:2417 ERROR: status = -30
(syz.0.0,5326,0):ocfs2_inode_lock_full_nested:2512 ERROR: status = -30
(syz.0.0,5326,0):ocfs2_reflink_inodes_lock:4748 ERROR: status = -30
==================================================================
BUG: KASAN: use-after-free in memcpy_from_folio include/linux/highmem.h:586 [inline]
BUG: KASAN: use-after-free in ocfs2_write_end_inline fs/ocfs2/aops.c:1915 [inline]
BUG: KASAN: use-after-free in ocfs2_write_end_nolock+0xbd9/0x18f0 fs/ocfs2/aops.c:1949
Write of size 4086 at addr ffff88805698d4d2 by task syz.0.0/5326

CPU: 0 UID: 0 PID: 5326 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
__asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106
memcpy_from_folio include/linux/highmem.h:586 [inline]
ocfs2_write_end_inline fs/ocfs2/aops.c:1915 [inline]
ocfs2_write_end_nolock+0xbd9/0x18f0 fs/ocfs2/aops.c:1949
ocfs2_write_end+0x58/0x90 fs/ocfs2/aops.c:2059
generic_perform_write+0x620/0x8f0 mm/filemap.c:4340
ocfs2_file_write_iter+0x1663/0x1ed0 fs/ocfs2/file.c:2476
iter_file_splice_write+0x9a1/0x10f0 fs/splice.c:736
do_splice_from fs/splice.c:936 [inline]
direct_splice_actor+0x101/0x160 fs/splice.c:1159
splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1103
do_splice_direct_actor fs/splice.c:1202 [inline]
do_splice_direct+0x195/0x290 fs/splice.c:1228
vfs_copy_file_range+0xb02/0x1370 fs/read_write.c:1634
__do_sys_copy_file_range fs/read_write.c:1683 [inline]
__se_sys_copy_file_range+0x2fb/0x480 fs/read_write.c:1650
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6962b9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6963b2ffe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000146
RAX: ffffffffffffffda RBX: 00007f6962e15fa0 RCX: 00007f6962b9c819
RDX: 0000000000000007 RSI: 00002000000001c0 RDI: 0000000000000009
RBP: 00007f6962c32c91 R08: ffffffffa003e45b R09: 0700000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6962e16038 R14: 00007f6962e15fa0 R15: 00007ffdd1b06d88
</TASK>

The buggy address belongs to the physical page:
page: refcount:2 mapcount:0 mapping:ffff88801cc2e6c8 index:0x854 pfn:0x5698d
memcg:ffff88801c6c8d40
aops:def_blk_aops ino:700000 dentry name(?):""
flags: 0x4fff38000004224(referenced|lru|workingset|private|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff38000004224 ffffea0000c8de48 ffffea00010e8748 ffff88801cc2e6c8
raw: 0000000000000854 ffff888047db69f8 00000002ffffffff ffff88801c6c8d40
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x148c48(GFP_NOFS|__GFP_MOVABLE|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL), pid 5326, tgid 5325 (syz.0.0), ts 85096096325, free_ts 85052438588
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline]
alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2575
folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2585
filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013
__filemap_get_folio_mpol+0x3fc/0xb00 mm/filemap.c:2011
__filemap_get_folio include/linux/pagemap.h:774 [inline]
grow_dev_folio fs/buffer.c:1047 [inline]
grow_buffers fs/buffer.c:1113 [inline]
__getblk_slow fs/buffer.c:1131 [inline]
bdev_getblk+0x1f6/0x6e0 fs/buffer.c:1458
__getblk include/linux/buffer_head.h:380 [inline]
sb_getblk include/linux/buffer_head.h:386 [inline]
ocfs2_read_blocks+0x57e/0x15e0 fs/ocfs2/buffer_head_io.c:236
ocfs2_read_inode_block_full fs/ocfs2/inode.c:1735 [inline]
ocfs2_read_inode_block+0xec/0x1d0 fs/ocfs2/inode.c:1749
ocfs2_assign_bh fs/ocfs2/dlmglue.c:2415 [inline]
ocfs2_inode_lock_full_nested+0x2ac/0x1bd0 fs/ocfs2/dlmglue.c:2510
ocfs2_reflink_inodes_lock+0x477/0xc50 fs/ocfs2/refcounttree.c:4744
ocfs2_remap_file_range+0x236/0x6f0 fs/ocfs2/file.c:2721
vfs_copy_file_range+0xd80/0x1370 fs/read_write.c:1600
__do_sys_copy_file_range fs/read_write.c:1683 [inline]
__se_sys_copy_file_range+0x2fb/0x480 fs/read_write.c:1650
page last free pid 5327 tgid 5325 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
folios_put_refs+0x789/0x8d0 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
mapping_try_invalidate+0x3c2/0x4c0 mm/truncate.c:579
loop_set_status+0x29b/0xe40 drivers/block/loop.c:1246
loop_set_status_old drivers/block/loop.c:1362 [inline]
lo_ioctl+0xce6/0x1fb0 drivers/block/loop.c:1551
blkdev_ioctl+0x5e3/0x740 block/ioctl.c:804
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff88805698df00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88805698df80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805698e000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88805698e080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805698e100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup