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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-20 18:16:34 -0500 |
|---|---|---|
| committer | Enric Balletbo i Serra <enric.balletbo@collabora.com> | 2020-03-22 11:15:28 +0100 |
| commit | e0db7c42b05f7b9d76174db56d683f0ec4f206c1 (patch) | |
| tree | 49aa7ff1a47926c3e184362d0d2a1bcda8b59669 | |
| parent | 45620da40f6fe627f6f98ba4f6edc2e43dd8d291 (diff) | |
| download | linux-stable-e0db7c42b05f7b9d76174db56d683f0ec4f206c1.tar.gz linux-stable-e0db7c42b05f7b9d76174db56d683f0ec4f206c1.tar.bz2 linux-stable-e0db7c42b05f7b9d76174db56d683f0ec4f206c1.zip | |
platform/chrome: wilco_ec: event: 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: Enric Balletbo i Serra <enric.balletbo@collabora.com>
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/event.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/platform/chrome/wilco_ec/event.c b/drivers/platform/chrome/wilco_ec/event.c index dba3d445623f..814518509739 100644 --- a/drivers/platform/chrome/wilco_ec/event.c +++ b/drivers/platform/chrome/wilco_ec/event.c @@ -79,7 +79,7 @@ static DEFINE_IDA(event_ida); struct ec_event { u16 size; u16 type; - u16 event[0]; + u16 event[]; } __packed; #define ec_event_num_words(ev) (ev->size - 1) @@ -96,7 +96,7 @@ struct ec_event_queue { int capacity; int head; int tail; - struct ec_event *entries[0]; + struct ec_event *entries[]; }; /* Maximum number of events to store in ec_event_queue */ |