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author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 13:53:23 -0500 |
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committer | Wei Liu <wei.liu@kernel.org> | 2020-05-20 09:13:59 +0000 |
commit | db5871e85533f06ffe1795c1cb9b9153860d1e4f (patch) | |
tree | 738dfd219a6c013257a36ea9c22960bf139dd8f4 /drivers/hv | |
parent | 723c425f2947dd0ecdde270cb8463b22b3e59603 (diff) | |
download | linux-db5871e85533f06ffe1795c1cb9b9153860d1e4f.tar.gz linux-db5871e85533f06ffe1795c1cb9b9153860d1e4f.tar.bz2 linux-db5871e85533f06ffe1795c1cb9b9153860d1e4f.zip |
vmbus: 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>
Link: https://lore.kernel.org/r/20200507185323.GA14416@embeddedor
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
0 files changed, 0 insertions, 0 deletions