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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-28 18:14:11 -0600
committerDavid S. Miller <davem@davemloft.net>2020-02-29 21:52:20 -0800
commit97a888c2ff6bbb92bdb0cb6cfff458cc412da788 (patch)
treeb9377299f0d604db51b26cd79cdb6e48bb9879fe /include/net/nexthop.h
parent2e7aaaa19cf226944c19fbefbbbbd76f9720b310 (diff)
net: nexthop: 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> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/nexthop.h')
-rw-r--r--include/net/nexthop.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index 331ebbc94fe7..c440ccc861fc 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -73,7 +73,7 @@ struct nh_group {
u16 num_nh;
bool mpath;
bool has_v4;
- struct nh_grp_entry nh_entries[0];
+ struct nh_grp_entry nh_entries[];
};
struct nexthop {