path: root/tools/testing/selftests/nsfs
diff options
authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-07 13:56:08 -0500
committerShuah Khan <skhan@linuxfoundation.org>2020-05-08 09:42:14 -0600
commitd8238f9eb6e0c175c8b657af20164eef6b30c71c (patch)
tree8da8ee066645d68f6b3b701fe2a8ffe828098db3 /tools/testing/selftests/nsfs
parentkselftests: dmabuf-heaps: Fix confused return value on expected error testing (diff)
tools/testing: Replace zero-length array with flexible-array
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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 <gustavoars@kernel.org> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Diffstat (limited to 'tools/testing/selftests/nsfs')
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/testing/selftests/nsfs/pidns.c b/tools/testing/selftests/nsfs/pidns.c
index e0d86e1668c0..e3c772c6a7c7 100644
--- a/tools/testing/selftests/nsfs/pidns.c
+++ b/tools/testing/selftests/nsfs/pidns.c
@@ -27,7 +27,7 @@
#define __stack_aligned__ __attribute__((aligned(16)))
struct cr_clone_arg {
char stack[128] __stack_aligned__;
- char stack_ptr[0];
+ char stack_ptr[];
static int child(void *args)