diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-12 13:52:31 -0600 |
|---|---|---|
| committer | Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> | 2020-03-06 22:18:07 +0100 |
| commit | 2f920c0f0e29268827c2894c6e8f237a78159718 (patch) | |
| tree | d207a6fd49dda02b7eb1e9a3e97bdfa15bf49d4f /drivers | |
| parent | e8897e4fe8f27d407b1e00ee0410fd3ec396275c (diff) | |
auxdisplay: charlcd: 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: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/auxdisplay/charlcd.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index 874c259a8829..c0da3820454b 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -88,7 +88,7 @@ struct charlcd_priv { int len; } esc_seq; - unsigned long long drvdata[0]; + unsigned long long drvdata[]; }; #define charlcd_to_priv(p) container_of(p, struct charlcd_priv, lcd) |