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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 13:54:51 -0500 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2020-05-12 11:54:08 +0300 |
| commit | e0e05f20c200c41b34294078bbc29d67bfd607ea (patch) | |
| tree | 8f8b04ea742f423fd348b7ee3956a23c9060fd58 /drivers/net/wireless/intel/ipw2x00/ipw2200.c | |
| parent | f2cd32a443da694ac4e28fbf4ac6f9d5cc63a539 (diff) | |
| download | linux-e0e05f20c200c41b34294078bbc29d67bfd607ea.tar.bz2 | |
ipw2x00: 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: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200507185451.GA14603@embeddedor
Diffstat (limited to 'drivers/net/wireless/intel/ipw2x00/ipw2200.c')
| -rw-r--r-- | drivers/net/wireless/intel/ipw2x00/ipw2200.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/wireless/intel/ipw2x00/ipw2200.c b/drivers/net/wireless/intel/ipw2x00/ipw2200.c index e9e686ad57b1..661e63bfc892 100644 --- a/drivers/net/wireless/intel/ipw2x00/ipw2200.c +++ b/drivers/net/wireless/intel/ipw2x00/ipw2200.c @@ -3386,7 +3386,7 @@ struct ipw_fw { __le32 boot_size; __le32 ucode_size; __le32 fw_size; - u8 data[0]; + u8 data[]; }; static int ipw_get_fw(struct ipw_priv *priv, |