Searched hist:"0 f0658636dab369f000430bc2858acbc30d9d5d9" (Results 1 – 1 of 1) sorted by relevance
| /linux/drivers/gpu/drm/qxl/ |
| H A D | qxl_cmd.c | diff 0f0658636dab369f000430bc2858acbc30d9d5d9 Wed Feb 12 20:33:44 CET 2020 Gustavo A. R. Silva <gustavo@embeddedor.com> drm/qxl: 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.
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>
Link: http://patchwork.freedesktop.org/patch/msgid/20200212193344.GA27929@embeddedor
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
|