From 82ea9d4fc05fb7a387db547c6a7c0aa6a3719616 Mon Sep 17 00:00:00 2001 From: Dmitry Antipov Date: Tue, 21 Jul 2026 13:28:40 +0300 Subject: [PATCH] ocfs2: always run deallocs on copy-on-write completion 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. Link: https://lore.kernel.org/20260721102840.387663-1-dmantipov@yandex.ru Link: https://lore.kernel.org/ocfs2-devel/f1d7e266-4b44-41b9-98c0-5b3868a8d9c3@yandex.ru [1] Fixes: 6f70fa519976 ("ocfs2: Add CoW support.") Signed-off-by: Dmitry Antipov Suggested-by: Joseph Qi Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Cc: Signed-off-by: Andrew Morton --- fs/ocfs2/refcounttree.c | 20 ++++++++------------ fs/ocfs2/xattr.c | 5 ++--- 2 files changed, 10 insertions(+), 15 deletions(-) diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c index 63d6cb326e30..d9f22b4a2654 100644 --- a/fs/ocfs2/refcounttree.c +++ b/fs/ocfs2/refcounttree.c @@ -3387,10 +3387,9 @@ static int ocfs2_replace_cow(struct ocfs2_cow_context *context) 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 @@ static int ocfs2_attach_refcount_tree(struct inode *inode, 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 @@ static int ocfs2_create_reflink_node(struct inode *s_inode, 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 inode *s_inode, } 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; } diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index d23364c30e1a..ed774bded974 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -7424,10 +7424,9 @@ int ocfs2_reflink_xattrs(struct inode *old_inode, 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;