From 573a73abc316ca6fe30fd52eaaf31c93077b2b23 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 27 Feb 2020 12:37:48 -0600 Subject: zorro: 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 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 Link: https://lore.kernel.org/r/20200227183748.GA31018@embeddedor Signed-off-by: Geert Uytterhoeven --- drivers/zorro/zorro.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/zorro/zorro.c b/drivers/zorro/zorro.c index 8eeb84c239db..47c733817903 100644 --- a/drivers/zorro/zorro.c +++ b/drivers/zorro/zorro.c @@ -41,7 +41,7 @@ struct zorro_dev *zorro_autocon; struct zorro_bus { struct device dev; - struct zorro_dev devices[0]; + struct zorro_dev devices[]; }; -- cgit v1.2.3