From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,stable@vger.kernel.org,piaojun@huawei.com,mark@fasheh.com,junxiao.bi@oracle.com,joseph.qi@linux.alibaba.com,jlbec@evilplan.org,heming.zhao@suse.com,gechangwei@live.cn,dmantipov@yandex.ru,akpm@linux-foundation.org
Subject: + ocfs2-always-run-deallocs-on-copy-on-write-completion.patch added to mm-nonmm-unstable branch
Date: Tue, 21 Jul 2026 17:11:43 -0700 [thread overview]
Message-ID: <20260722001144.494F21F000E9@smtp.kernel.org> (raw)
The patch titled
Subject: ocfs2: always run deallocs on copy-on-write completion
has been added to the -mm mm-nonmm-unstable branch. Its filename is
ocfs2-always-run-deallocs-on-copy-on-write-completion.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-always-run-deallocs-on-copy-on-write-completion.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Dmitry Antipov <dmantipov@yandex.ru>
Subject: ocfs2: always run deallocs on copy-on-write completion
Date: Tue, 21 Jul 2026 13:28:40 +0300
Local fuzzing of 6.12.94 has found the following memory leak
caused by doing 'copy_file_range()' within the same filesystem:
unreferenced object 0xffff88812192c980 (size 32):
comm "syz.0.49", pid 12095, jiffies 4294964143
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 08 00 00 00 00 00 00 00 ................
c0 c5 92 21 81 88 ff ff 00 02 00 00 00 06 00 00 ...!............
backtrace (crc 7068d63f):
kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
slab_post_alloc_hook mm/slub.c:4152 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
__kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358
kmalloc_noprof include/linux/slab.h:878 [inline]
ocfs2_find_per_slot_free_list fs/ocfs2/alloc.c:6618 [inline]
ocfs2_cache_block_dealloc+0x155/0x4b0 fs/ocfs2/alloc.c:6786
ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline]
ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613
ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline]
__ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985
ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237
ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825
ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138
ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098
ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline]
ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline]
ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline]
ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470
ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline]
ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451
iter_file_splice_write+0x890/0xf60 fs/splice.c:743
do_splice_from fs/splice.c:944 [inline]
direct_splice_actor+0x232/0x480 fs/splice.c:1167
splice_direct_to_actor+0x4b4/0xb60 fs/splice.c:1111
do_splice_direct_actor fs/splice.c:1210 [inline]
do_splice_direct+0x10f/0x1c0 fs/splice.c:1236
do_sendfile+0x430/0xbf0 fs/read_write.c:1388
unreferenced object 0xffff88812192c5c0 (size 32):
comm "syz.0.49", pid 12095, jiffies 4294964143
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
29 70 00 00 00 00 00 00 19 00 00 00 00 00 00 00 )p..............
backtrace (crc afec850f):
kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
slab_post_alloc_hook mm/slub.c:4152 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
__kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
ocfs2_cache_block_dealloc+0x25c/0x4b0 fs/ocfs2/alloc.c:6793
ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline]
ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613
ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline]
__ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985
ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237
ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825
ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138
ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098
ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline]
ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline]
ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline]
ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470
ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline]
ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451
iter_file_splice_write+0x890/0xf60 fs/splice.c:743
do_splice_from fs/splice.c:944 [inline]
direct_splice_actor+0x232/0x480 fs/splice.c:1167
splice_direct_to_actor+0x4b4/0xb60 fs/splice.c:1111
do_splice_direct_actor fs/splice.c:1210 [inline]
do_splice_direct+0x10f/0x1c0 fs/splice.c:1236
do_sendfile+0x430/0xbf0 fs/read_write.c:1388
This happens when 'ocfs2_cache_block_dealloc()' called from
'ocfs2_cache_extent_block_free()' uses the suballocator to
schedule extent removal, so 'ocfs2_run_deallocs()' should
be run unconditionally to complete the removal with
'ocfs2_free_cached_blocks()'. An extra semi-automated static
analysis [1] suspects that the same scenario looks possible in
'ocfs2_attach_refcount_tree()' and 'ocfs2_reflink_remap_blocks()'
as well, but, since 'ocfs2_run_deallocs()' is a safe no-op for
an empty dealloc context, 'ocfs2_create_reflink_node()' and
'ocfs2_reflink_xattrs()' may be adjusted in the same way too,
thus keeping the code pattern consistent.
[1] https://lore.kernel.org/ocfs2-devel/f1d7e266-4b44-41b9-98c0-5b3868a8d9c3@yandex.ru
Link: https://lore.kernel.org/20260721102840.387663-1-dmantipov@yandex.ru
Fixes: 6f70fa519976 ("ocfs2: Add CoW support.")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Suggested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/ocfs2/refcounttree.c | 20 ++++++++------------
fs/ocfs2/xattr.c | 5 ++---
2 files changed, 10 insertions(+), 15 deletions(-)
--- a/fs/ocfs2/refcounttree.c~ocfs2-always-run-deallocs-on-copy-on-write-completion
+++ a/fs/ocfs2/refcounttree.c
@@ -3387,10 +3387,9 @@ static int ocfs2_replace_cow(struct ocfs
cow_start += num_clusters;
}
- if (ocfs2_dealloc_has_cluster(&context->dealloc)) {
+ if (ocfs2_dealloc_has_cluster(&context->dealloc))
ocfs2_schedule_truncate_log_flush(osb, 1);
- ocfs2_run_deallocs(osb, &context->dealloc);
- }
+ ocfs2_run_deallocs(osb, &context->dealloc);
return ret;
}
@@ -3873,10 +3872,9 @@ unlock:
ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
brelse(ref_root_bh);
- if (!ret && ocfs2_dealloc_has_cluster(&dealloc)) {
+ if (!ret && ocfs2_dealloc_has_cluster(&dealloc))
ocfs2_schedule_truncate_log_flush(osb, 1);
- ocfs2_run_deallocs(osb, &dealloc);
- }
+ ocfs2_run_deallocs(osb, &dealloc);
out:
/*
* Empty the extent map so that we may get the right extent
@@ -4162,10 +4160,9 @@ out_unlock_refcount:
ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
brelse(ref_root_bh);
out:
- if (ocfs2_dealloc_has_cluster(&dealloc)) {
+ if (ocfs2_dealloc_has_cluster(&dealloc))
ocfs2_schedule_truncate_log_flush(osb, 1);
- ocfs2_run_deallocs(osb, &dealloc);
- }
+ ocfs2_run_deallocs(osb, &dealloc);
return ret;
}
@@ -4718,10 +4715,9 @@ loff_t ocfs2_reflink_remap_blocks(struct
}
out:
- if (ocfs2_dealloc_has_cluster(&dealloc)) {
+ if (ocfs2_dealloc_has_cluster(&dealloc))
ocfs2_schedule_truncate_log_flush(osb, 1);
- ocfs2_run_deallocs(osb, &dealloc);
- }
+ ocfs2_run_deallocs(osb, &dealloc);
return ret;
}
--- a/fs/ocfs2/xattr.c~ocfs2-always-run-deallocs-on-copy-on-write-completion
+++ a/fs/ocfs2/xattr.c
@@ -7424,10 +7424,9 @@ out_unlock:
ref_tree, 1);
brelse(ref_root_bh);
- if (ocfs2_dealloc_has_cluster(&dealloc)) {
+ if (ocfs2_dealloc_has_cluster(&dealloc))
ocfs2_schedule_truncate_log_flush(OCFS2_SB(old_inode->i_sb), 1);
- ocfs2_run_deallocs(OCFS2_SB(old_inode->i_sb), &dealloc);
- }
+ ocfs2_run_deallocs(OCFS2_SB(old_inode->i_sb), &dealloc);
out:
return ret;
_
Patches currently in -mm which might be from dmantipov@yandex.ru are
ocfs2-do-not-use-make_bad_inode-in-ocfs2_read_inode_block_full.patch
ocfs2-always-run-deallocs-on-copy-on-write-completion.patch
reply other threads:[~2026-07-22 0:11 UTC|newest]
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