diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-17 14:07:19 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-17 19:05:06 -0800 |
| commit | 2b73812483e953ebff35d5624149d645df7a3022 (patch) | |
| tree | 7ece3b4dd5627afd0eba5de77add5c6294d4b8e6 | |
| parent | fbfc8502af526578039dc89426224943d199c019 (diff) | |
net: netlink: 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-- | net/netlink/af_netlink.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 4e31721e7293..bced11032681 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -71,7 +71,7 @@ struct listeners { struct rcu_head rcu; - unsigned long masks[0]; + unsigned long masks[]; }; /* state bits */ |