diff options
| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 13:59:14 -0500 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2020-05-12 11:55:22 +0300 |
| commit | 174812346c30321158046d879912c85d638cd1b7 (patch) | |
| tree | a086873cf385246a74ab7b67bdd68a09d402f318 | |
| parent | 8863b1212aab2c738be9526f90389bc0fc18f90f (diff) | |
mwl8k: 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/20200507185914.GA15124@embeddedor
| -rw-r--r-- | drivers/net/wireless/marvell/mwl8k.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/wireless/marvell/mwl8k.c b/drivers/net/wireless/marvell/mwl8k.c index 47fb4b3ea004..97f23f93f6e7 100644 --- a/drivers/net/wireless/marvell/mwl8k.c +++ b/drivers/net/wireless/marvell/mwl8k.c @@ -2668,7 +2668,7 @@ struct mwl8k_cmd_mac_multicast_adr { struct mwl8k_cmd_pkt header; __le16 action; __le16 numaddr; - __u8 addr[0][ETH_ALEN]; + __u8 addr[][ETH_ALEN]; }; #define MWL8K_ENABLE_RX_DIRECTED 0x0001 |