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 --- include/drm/bridge/mhl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/drm/bridge/mhl.h b/include/drm/bridge/mhl.h index 1cc77bf38324..d96626a0e3fa 100644 --- a/include/drm/bridge/mhl.h +++ b/include/drm/bridge/mhl.h @@ -327,13 +327,13 @@ struct mhl_burst_bits_per_pixel_fmt { struct { u8 stream_id; u8 pixel_format; - } __packed desc[0]; + } __packed desc[]; } __packed;
struct mhl_burst_emsc_support { struct mhl3_burst_header hdr; u8 num_entries; - __be16 burst_id[0]; + __be16 burst_id[]; } __packed;
struct mhl_burst_audio_descr {