diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-21 19:00:05 +0300 |
|---|---|---|
| committer | Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2020-03-02 18:32:17 +0300 |
| commit | 451787d3e2ac3a25abae91792b7154ee533b65c6 (patch) | |
| tree | a02afdc4fb56590b6267d31a13a5abcfffa62e30 | |
| parent | 9dff9a3666f15f4c76d9ddfa52744a1e86fd0ff6 (diff) | |
| download | linux-451787d3e2ac3a25abae91792b7154ee533b65c6.tar.xz | |
video: 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 <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200221160005.GA13552@embeddedor
| -rw-r--r-- | drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 | ||||
| -rw-r--r-- | drivers/video/fbdev/ssd1307fb.c | 2 | ||||
| -rw-r--r-- | include/video/mmp_disp.h | 2 |
3 files changed, 3 insertions, 3 deletions
diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h index 335d4983dc52..167585a889d3 100644 --- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h +++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h @@ -1406,7 +1406,7 @@ struct mmphw_ctrl { /*pathes*/ int path_num; - struct mmphw_path_plat path_plats[0]; + struct mmphw_path_plat path_plats[]; }; static inline int overlay_is_vid(struct mmp_overlay *overlay) diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 1a0bd78f9345..12fa1050f3eb 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -89,7 +89,7 @@ struct ssd1307fb_par { struct ssd1307fb_array { u8 type; - u8 data[0]; + u8 data[]; }; static const struct fb_fix_screeninfo ssd1307fb_fix = { diff --git a/include/video/mmp_disp.h b/include/video/mmp_disp.h index 1f9bc133e230..77252cb46361 100644 --- a/include/video/mmp_disp.h +++ b/include/video/mmp_disp.h @@ -231,7 +231,7 @@ struct mmp_path { /* layers */ int overlay_num; - struct mmp_overlay overlays[0]; + struct mmp_overlay overlays[]; }; extern struct mmp_path *mmp_get_path(const char *name); |