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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-24 01:59:00 +0300
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 23:44:55 +0300
commit0ead33642f1df89699f2e4dda8eea59c326b68f6 (patch)
treebca8a2fdcf0f8d5fd2402c68915316b9bab887d1
parent89f60a5d9bf5a6b9b16dfdd56a91c4a2d7b8830d (diff)
downloadlinux-0ead33642f1df89699f2e4dda8eea59c326b68f6.tar.xz
igmp.h: 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>
-rw-r--r--include/linux/igmp.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index 463047d0190b..faa6586a5783 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -38,7 +38,7 @@ struct ip_sf_socklist {
unsigned int sl_max;
unsigned int sl_count;
struct rcu_head rcu;
- __be32 sl_addr[0];
+ __be32 sl_addr[];
};
#define IP_SFLSIZE(count) (sizeof(struct ip_sf_socklist) + \