diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 16:43:24 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-28 23:08:37 +0300 |
| commit | d2afb41ae60435cbe5d9d1078a7d90de04e571b8 (patch) | |
| tree | d6a4823b544ef0768b8b8a052b7ee49da15eff0e /net | |
| parent | b0c9a2d9a8ee13ec68ff5f80fdd74bd83272f967 (diff) | |
| download | linux-d2afb41ae60435cbe5d9d1078a7d90de04e571b8.tar.xz | |
net: core: 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')
| -rw-r--r-- | net/core/bpf_sk_storage.c | 2 | ||||
| -rw-r--r-- | net/core/devlink.c | 2 | ||||
| -rw-r--r-- | net/core/drop_monitor.c | 2 |
3 files changed, 3 insertions, 3 deletions
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 3ab23f698221..427cfbc0d50d 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -60,7 +60,7 @@ struct bpf_sk_storage_data { * the number of cachelines access during the cache hit case. */ struct bpf_sk_storage_map __rcu *smap; - u8 data[0] __aligned(8); + u8 data[] __aligned(8); }; /* Linked to bpf_sk_storage and bpf_sk_storage_map */ diff --git a/net/core/devlink.c b/net/core/devlink.c index f8af5e2d748b..295d761cbfb1 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4232,7 +4232,7 @@ struct devlink_fmsg_item { int attrtype; u8 nla_type; u16 len; - int value[0]; + int value[]; }; struct devlink_fmsg { diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index d58c1c45a895..8e33cec9fc4e 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -68,7 +68,7 @@ struct net_dm_hw_entry { struct net_dm_hw_entries { u32 num_entries; - struct net_dm_hw_entry entries[0]; + struct net_dm_hw_entry entries[]; }; struct per_cpu_dm_data { |