diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 19:05:02 -0600 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2020-02-29 21:52:20 -0800 |
commit | 08ca27d027c238ed3f9b9968d349cebde44d99a6 (patch) | |
tree | 16da06932c89de8b052eb889f5750240790275a4 | |
parent | 8661b6e7c46408bb6a74d3a1d77ce9af35f584d8 (diff) | |
download | linux-08ca27d027c238ed3f9b9968d349cebde44d99a6.tar.bz2 |
neighbour: 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: David S. Miller <davem@davemloft.net>
-rw-r--r-- | include/net/neighbour.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 8ec77bfdc1a4..e1476775769c 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -174,7 +174,7 @@ struct pneigh_entry { struct net_device *dev; u8 flags; u8 protocol; - u8 key[0]; + u8 key[]; }; /* |