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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-29 04:02:54 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-01 08:52:20 +0300 |
| commit | 8661b6e7c46408bb6a74d3a1d77ce9af35f584d8 (patch) | |
| tree | 1fdb3cebd0a5da5c6bd4f593263890bf22049b58 | |
| parent | a79b41ec983620ee43c35fd9082ec49816654a71 (diff) | |
| download | linux-8661b6e7c46408bb6a74d3a1d77ce9af35f584d8.tar.xz | |
net: flow_offload: 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>
| -rw-r--r-- | include/net/flow_offload.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h index 4e864c34a1b0..cd3510ac66b0 100644 --- a/include/net/flow_offload.h +++ b/include/net/flow_offload.h @@ -229,7 +229,7 @@ struct flow_action_entry { struct flow_action { unsigned int num_entries; - struct flow_action_entry entries[0]; + struct flow_action_entry entries[]; }; static inline bool flow_action_has_entries(const struct flow_action *action) |