[v1] jfs: fix metapage reference count leak in dbAllocCtl

[PATCH] jfs: fix metapage reference count leak in dbAllocCtl

Posted by Zheng Yu 2 months, 1 week ago

In dbAllocCtl(), read_metapage() increases the reference count of the
metapage. However, when dp->tree.budmin < 0, the function returns -EIO
without calling release_metapage() to decrease the reference count,
leading to a memory leak.

Add release_metapage(mp) before the error return to properly manage
the metapage reference count and prevent the leak.

Fixes: 51a203470f502a64a3da8dcea51c4748e8267a6c ("jfs: fix shift-out-of-bounds in dbSplit")

Signed-off-by: Zheng Yu <zheng.yu@northwestern.edu>
---
 fs/jfs/jfs_dmap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 35e063c9f3a4..5a877261c3fe 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -1809,8 +1809,10 @@ dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
 			return -EIO;
 		dp = (struct dmap *) mp->data;
 
-		if (dp->tree.budmin < 0)
+		if (dp->tree.budmin < 0) {
+			release_metapage(mp);
 			return -EIO;
+		}
 
 		/* try to allocate the blocks.
 		 */
-- 
2.43.0

Re: [PATCH] jfs: fix metapage reference count leak in dbAllocCtl

Posted by Markus Elfring 2 months, 1 week ago

…
> +++ b/fs/jfs/jfs_dmap.c
> @@ -1809,8 +1809,10 @@ dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
>  			return -EIO;
>  		dp = (struct dmap *) mp->data;
>  
> -		if (dp->tree.budmin < 0)
> +		if (dp->tree.budmin < 0) {
> +			release_metapage(mp);
>  			return -EIO;
> +		}
…

Would it be a bit nicer to use an additional label for this case?

			rc = -EIO;
			goto release_metapage;


Regards,
Markus