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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-17 14:02:36 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-17 19:05:06 -0800 |
| commit | fbfc8502af526578039dc89426224943d199c019 (patch) | |
| tree | 18195e815c9a498ec24b9d8d2d656a0b76333f01 /net/switchdev | |
| parent | 45a4296b6e55ef2fbbe5946582822daf8f0f2e71 (diff) | |
| download | linux-fbfc8502af526578039dc89426224943d199c019.tar.bz2 | |
net: switchdev: 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/switchdev')
| -rw-r--r-- | net/switchdev/switchdev.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c index 3a1d428c1336..60630762a748 100644 --- a/net/switchdev/switchdev.c +++ b/net/switchdev/switchdev.c @@ -29,7 +29,7 @@ struct switchdev_deferred_item { struct list_head list; struct net_device *dev; switchdev_deferred_func_t *func; - unsigned long data[0]; + unsigned long data[]; }; static struct switchdev_deferred_item *switchdev_deferred_dequeue(void) |