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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-17 14:07:19 -0600
committerDavid S. Miller <davem@davemloft.net>2020-02-17 19:05:06 -0800
commit2b73812483e953ebff35d5624149d645df7a3022 (patch)
tree7ece3b4dd5627afd0eba5de77add5c6294d4b8e6 /net/netlink
parentfbfc8502af526578039dc89426224943d199c019 (diff)
downloadlinux-2b73812483e953ebff35d5624149d645df7a3022.tar.bz2
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>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c2
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 */