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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-09 10:57:22 -0500
committerDavid Teigland <teigland@redhat.com>2020-05-12 14:06:15 -0500
commit3c80d3794dac5b0f50132846113a120d881462ec (patch)
tree294161974355fa5be8697fd458132258eeda2b25 /fs/dlm
parenta4e439a6f628a52f7074c9d73ec7eb4f6c1a4dfc (diff)
dlm: user: 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 Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/user.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 5264bac75115..e5cefa90b1ce 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -46,7 +46,7 @@ struct dlm_lock_params32 {
__u32 bastaddr;
__u32 lksb;
char lvb[DLM_USER_LVB_LEN];
- char name[0];
+ char name[];
};
struct dlm_write_request32 {