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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-27 14:58:44 -0600
committerDavid S. Miller <davem@davemloft.net>2020-02-29 21:27:02 -0800
commitb90feaff2a2cbf339069adec4bfd6091cfb44b50 (patch)
tree93bd8729ec50413d5a530bb7567abf4302de0fbd /net/sched/sch_atm.c
parent9f0ca0c1a50a7de5c71970aa452941199ed210d9 (diff)
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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.c2
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 {