linux-kernel - [PATCH] exfat: fix refcount leak in exfat

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Message-ID: <aPZOpRfVPZCP8vPw@chcpu18>
Date: Mon, 20 Oct 2025 15:00:53 +0000
From: Shuhao Fu <sfual@....ust.hk>
To: Namjae Jeon <linkinjeon@...nel.org>, Sungjong Seo <sj1557.seo@...sung.com>
Cc: Yuezhang Mo <yuezhang.mo@...y.com>, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] exfat: fix refcount leak in exfat_find

Fix refcount leaks in `exfat_find` related to `exfat_get_dentry_set`.

Function `exfat_get_dentry_set` would increase the reference counter of 
`es->bh` on success. Therefore, `exfat_put_dentry_set` must be called
after `exfat_get_dentry_set` to ensure refcount consistency. In 
`exfat_find`, two branchs fail to call `exfat_put_dentry_set`, leading
to possible resource leaks.

Fixes: 82ebecdc74ff ("exfat: fix improper check of dentry.stream.valid_size")
Fixes: 13940cef9549 ("exfat: add a check for invalid data size")
Signed-off-by: Shuhao Fu <sfual@....ust.hk>
---
 fs/exfat/namei.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 745dce29d..083a9d790 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -646,11 +646,13 @@ static int exfat_find(struct inode *dir, const struct qstr *qname,
 	info->size = le64_to_cpu(ep2->dentry.stream.size);
 
 	if (info->valid_size < 0) {
+		exfat_put_dentry_set(&es, false);
 		exfat_fs_error(sb, "data valid size is invalid(%lld)", info->valid_size);
 		return -EIO;
 	}
 
 	if (unlikely(EXFAT_B_TO_CLU_ROUND_UP(info->size, sbi) > sbi->used_clusters)) {
+		exfat_put_dentry_set(&es, false);
 		exfat_fs_error(sb, "data size is invalid(%lld)", info->size);
 		return -EIO;
 	}
-- 
2.39.5 (Apple Git-154)