On 06/03/2025 13:28, Zhiyu Zhang wrote:
When mounting a squashfs fails, squashfs_cache_init() may return an error
pointer (e.g., -ENOMEM) instead of NULL. However, squashfs_cache_delete()
only checks for a NULL cache, and attempts to dereference the invalid
pointer. This leads to a kernel crash (BUG: unable to handle kernel paging
request in squashfs_cache_delete).
This patch fixes the issue by checking IS_ERR(cache) before accessing it.
Fixes: 49ff29240ebb ("squashfs: make squashfs_cache_init() return ERR_PTR(-ENOMEM)")
Reported-by: Zhiyu Zhang <zhiyuzhang999@xxxxxxxxx>
Closes: https://lore.kernel.org/linux-fsdevel/CALf2hKvaq8B4u5yfrE+BYt7aNguao99mfWxHngA+=o5hwzjdOg@xxxxxxxxxxxxxx/
Tested-by: Zhiyu Zhang <zhiyuzhang999@xxxxxxxxx>
Signed-off-by: Zhiyu Zhang <zhiyuzhang999@xxxxxxxxx>
---
fs/squashfs/cache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index 4db0d2b0aab8..181260e72680 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -198,7 +198,7 @@ void squashfs_cache_delete(struct squashfs_cache *cache)
{
int i, j;
- if (cache == NULL)
+ if (IS_ERR(cache) || cache == NULL)
return;
for (i = 0; i < cache->entries; i++) {
Looks good to me.
Reviewed-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
