diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-27 14:58:44 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-29 21:27:02 -0800 |
| commit | b90feaff2a2cbf339069adec4bfd6091cfb44b50 (patch) | |
| tree | 93bd8729ec50413d5a530bb7567abf4302de0fbd /net/sched/sch_atm.c | |
| parent | 9f0ca0c1a50a7de5c71970aa452941199ed210d9 (diff) | |
net: sched: 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/sched/sch_atm.c')
| -rw-r--r-- | net/sched/sch_atm.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c index f4f9b8cdbffb..ee12ca9f55b4 100644 --- a/net/sched/sch_atm.c +++ b/net/sched/sch_atm.c @@ -58,7 +58,7 @@ struct atm_flow_data { struct atm_flow_data *excess; /* flow for excess traffic; NULL to set CLP instead */ int hdr_len; - unsigned char hdr[0]; /* header data; MUST BE LAST */ + unsigned char hdr[]; /* header data; MUST BE LAST */ }; struct atm_qdisc_data { |