@@ -61,7 +61,7 @@ struct jffs2_sum_dirent_flash
jint32_t ino; /* == zero for unlink */
uint8_t nsize; /* dirent name size */
uint8_t type; /* dirent type */
- uint8_t name[0]; /* dirent name */
+ uint8_t name[]; /* dirent name */
} __attribute__((packed));
struct jffs2_sum_xattr_flash
@@ -117,7 +117,7 @@ struct jffs2_sum_dirent_mem
jint32_t ino; /* == zero for unlink */
uint8_t nsize; /* dirent name size */
uint8_t type; /* dirent type */
- uint8_t name[0]; /* dirent name */
+ uint8_t name[]; /* dirent name */
} __attribute__((packed));
struct jffs2_sum_xattr_mem
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- fs/jffs2/summary.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)