diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-19 23:23:52 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-07-04 11:55:52 +0200 |
| commit | 7cd08d6eed2772e5ac759063a0287c5ff4551a91 (patch) | |
| tree | 9ec78473c87aa1c9dd6f1b9e22645ade74eff091 /drivers/media/usb | |
| parent | 50795910160e78c1bee6b27d8d7a3f93e8b7d48d (diff) | |
media: usb: pwc: pwc.h: 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: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'drivers/media/usb')
| -rw-r--r-- | drivers/media/usb/pwc/pwc.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/media/usb/pwc/pwc.h b/drivers/media/usb/pwc/pwc.h index 3362962d0d00..b02a3c7b7742 100644 --- a/drivers/media/usb/pwc/pwc.h +++ b/drivers/media/usb/pwc/pwc.h @@ -193,7 +193,7 @@ struct pwc_raw_frame { decompressor) */ __u8 cmd[4]; /* the four byte of the command (in case of nala, only the first 3 bytes is filled) */ - __u8 rawframe[0]; /* frame_size = H / 4 * vbandlength */ + __u8 rawframe[]; /* frame_size = H / 4 * vbandlength */ } __packed; /* intermediate buffers with raw data from the USB cam */ |