diff options
| author |   Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 13:53:01 -0500 |
|---|---|---|
| committer |   Li Yang <leoyang.li@nxp.com> | 2020-05-22 16:19:31 -0500 |
| commit | d3e81989c0f028aa80cb97fcba83df40585b640d (patch) | |
| tree | a450c086b5e10d9f7f7c9a41250c972d236b0617 /include/linux/fsl | |
| parent | Linux 5.7-rc1 (diff) | |
| download | wireguard-linux-d3e81989c0f028aa80cb97fcba83df40585b640d.tar.xz wireguard-linux-d3e81989c0f028aa80cb97fcba83df40585b640d.zip | |
treewide: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Diffstat (limited to 'include/linux/fsl')
| -rw-r--r-- | include/linux/fsl/bestcomm/bestcomm.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/fsl/bestcomm/bestcomm.h b/include/linux/fsl/bestcomm/bestcomm.h index a0e2e6b19b57..154e541ce57e 100644 --- a/include/linux/fsl/bestcomm/bestcomm.h +++ b/include/linux/fsl/bestcomm/bestcomm.h @@ -27,7 +27,7 @@ */ struct bcom_bd { u32 status; - u32 data[0]; /* variable payload size */ + u32 data[]; /* variable payload size */ }; /* ======================================================================== */ |