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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-28 07:26:15 -0600
committerDavid S. Miller <davem@davemloft.net>2020-02-28 12:08:37 -0800
commit680a93166e80e43e3ff85be06005c5cfa492d852 (patch)
tree853ebe2b13270e4e82a448b4d56c98e86f05704b /net/mpls
parent95e486f5519848ca4c2f2645cbe120de5df133f3 (diff)
downloadlinux-stericsson-680a93166e80e43e3ff85be06005c5cfa492d852.tar.gz
net: mpls: 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/mpls')
-rw-r--r--net/mpls/internal.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index 768a302879b4..0e9aa94adc07 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -98,7 +98,7 @@ struct mpls_nh { /* next hop label forwarding entry */
u8 nh_via_table;
u8 nh_reserved1;
- u32 nh_label[0];
+ u32 nh_label[];
};
/* offset of via from beginning of mpls_nh */
@@ -154,7 +154,7 @@ struct mpls_route { /* next hop label forwarding entry */
u8 rt_nh_size;
u8 rt_via_offset;
u8 rt_reserved1;
- struct mpls_nh rt_nh[0];
+ struct mpls_nh rt_nh[];
};
#define for_nexthops(rt) { \