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| author |   Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-26 15:23:17 -0600 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-02-27 12:06:55 -0800 |
| commit | 37e1244a79fd248ed31281259b478bc945b7bd4b (patch) | |
| tree | e9b160dfe866ac93cbeffa9213c07d913d127519 /drivers/net/wan | |
| parent | NFC: Replace zero-length array with flexible-array member (diff) | |
| download | wireguard-linux-37e1244a79fd248ed31281259b478bc945b7bd4b.tar.xz wireguard-linux-37e1244a79fd248ed31281259b478bc945b7bd4b.zip | |
WAN: 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 'drivers/net/wan')
| -rw-r--r-- | drivers/net/wan/farsync.h | 2 | ||||
| -rw-r--r-- | drivers/net/wan/wanxl.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/wan/farsync.h b/drivers/net/wan/farsync.h index 47b8e36f97ab..5f43568a9715 100644 --- a/drivers/net/wan/farsync.h +++ b/drivers/net/wan/farsync.h @@ -65,7 +65,7 @@ struct fstioc_write { unsigned int size; unsigned int offset; - unsigned char data[0]; + unsigned char data[]; }; diff --git a/drivers/net/wan/wanxl.c b/drivers/net/wan/wanxl.c index 23f93f1c815d..499f7cd19a4a 100644 --- a/drivers/net/wan/wanxl.c +++ b/drivers/net/wan/wanxl.c @@ -78,7 +78,7 @@ struct card { struct sk_buff *rx_skbs[RX_QUEUE_LENGTH]; struct card_status *status; /* shared between host and card */ dma_addr_t status_address; - struct port ports[0]; /* 1 - 4 port structures follow */ + struct port ports[]; /* 1 - 4 port structures follow */ }; |