From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Subject: lib/bch.c: replace zero-length array with flexible-array member
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
inadvertenly introduced[3] to the codebase from now on.
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")
Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/bch.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/bch.c~lib-bch-replace-zero-length-array-with-flexible-array-member
+++ a/lib/bch.c
@@ -102,7 +102,7 @@
*/
struct gf_poly {
unsigned int deg; /* polynomial degree */
- unsigned int c[0]; /* polynomial terms */
+ unsigned int c[]; /* polynomial terms */
};
/* given its degree, compute a polynomial size in bytes */
_
