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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 22:01:33 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-05-11 23:18:54 +0300 |
| commit | c2dfc7d2a9be9a14897eab6dd27eeea1bd4ea79b (patch) | |
| tree | 2866028f093729d1656ab3d96bb0179b7589f6f9 | |
| parent | 0fa39d6dd0478b080a420aa764280e1a3bdb0cee (diff) | |
| download | linux-c2dfc7d2a9be9a14897eab6dd27eeea1bd4ea79b.tar.xz | |
net: atarilance: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/amd/atarilance.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/ethernet/amd/atarilance.c b/drivers/net/ethernet/amd/atarilance.c index 4e36122609a3..961796abab35 100644 --- a/drivers/net/ethernet/amd/atarilance.c +++ b/drivers/net/ethernet/amd/atarilance.c @@ -156,7 +156,7 @@ struct lance_memory { struct lance_init_block init; struct lance_tx_head tx_head[TX_RING_SIZE]; struct lance_rx_head rx_head[RX_RING_SIZE]; - char packet_area[0]; /* packet data follow after the + char packet_area[]; /* packet data follow after the * init block and the ring * descriptors and are located * at runtime */ |