diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-02 06:03:52 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-02 11:16:28 -0800 |
| commit | a53110609c728fc0316cc09fee7ea17ebf93c684 (patch) | |
| tree | 11d21db2a8c5c80c18d1a4a3de20183e08b5aa8d /include/net/ip_fib.h | |
| parent | 1776658da830eb024b63ac34167dfd4bd6c21cf9 (diff) | |
| download | linux-a53110609c728fc0316cc09fee7ea17ebf93c684.tar.gz | |
net: ip_fib: 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 'include/net/ip_fib.h')
| -rw-r--r-- | include/net/ip_fib.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index 6a1ae49809de58..dabe398bee4c68 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h @@ -153,7 +153,7 @@ struct fib_info { bool nh_updated; struct nexthop *nh; struct rcu_head rcu; - struct fib_nh fib_nh[0]; + struct fib_nh fib_nh[]; }; @@ -250,7 +250,7 @@ struct fib_table { int tb_num_default; struct rcu_head rcu; unsigned long *tb_data; - unsigned long __data[0]; + unsigned long __data[]; }; struct fib_dump_filter { |