diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-05 05:06:44 -0600 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2020-03-05 14:55:48 -0800 |
commit | 5de3a2386ec39f573ae7733db4b506ad850ce015 (patch) | |
tree | a645a6cbfbfe91b2e430203114a2bee8d8bce961 | |
parent | 6349021701d0ba2e84e2be440258d81e198c3392 (diff) | |
download | linux-5de3a2386ec39f573ae7733db4b506ad850ce015.tar.bz2 |
net: tulip: 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-- | drivers/net/ethernet/dec/tulip/tulip.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/ethernet/dec/tulip/tulip.h b/drivers/net/ethernet/dec/tulip/tulip.h index b458140aeaef..815907259048 100644 --- a/drivers/net/ethernet/dec/tulip/tulip.h +++ b/drivers/net/ethernet/dec/tulip/tulip.h @@ -381,7 +381,7 @@ struct mediatable { unsigned has_reset:6; u32 csr15dir; u32 csr15val; /* 21143 NWay setting. */ - struct medialeaf mleaf[0]; + struct medialeaf mleaf[]; }; |