summaryrefslogtreecommitdiff
path: root/kernel/bpf/bpf_struct_ops.c
diff options
context:
space:
mode:
authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-26 18:17:44 -0600
committerDaniel Borkmann <daniel@iogearbox.net>2020-02-28 01:21:02 +0100
commitd7f10df86202273155a9d8f8553bc2ad28e0dd46 (patch)
treee253c06e6c409afbff1f057a5376fc77ac1dc01f /kernel/bpf/bpf_struct_ops.c
parent4bc988464bb193d67c93ddb2fcd1de127d815b6c (diff)
downloadlinux-d7f10df86202273155a9d8f8553bc2ad28e0dd46.tar.gz
bpf: 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: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200227001744.GA3317@embeddedor
Diffstat (limited to 'kernel/bpf/bpf_struct_ops.c')
-rw-r--r--kernel/bpf/bpf_struct_ops.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 042f95534f86..c498f0fffb40 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -23,7 +23,7 @@ enum bpf_struct_ops_state {
struct bpf_struct_ops_value {
BPF_STRUCT_OPS_COMMON_VALUE;
- char data[0] ____cacheline_aligned_in_smp;
+ char data[] ____cacheline_aligned_in_smp;
};
struct bpf_struct_ops_map {