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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-09 16:57:22 +0100 |
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committer | David Teigland <teigland@redhat.com> | 2020-05-12 21:06:15 +0200 |
commit | 3c80d3794dac5b0f50132846113a120d881462ec (patch) | |
tree | 294161974355fa5be8697fd458132258eeda2b25 /fs/dlm | |
parent | dlm: dlm_internal: Replace zero-length array with flexible-array member (diff) | |
download | linux-3c80d3794dac5b0f50132846113a120d881462ec.tar.xz linux-3c80d3794dac5b0f50132846113a120d881462ec.zip |
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.c | 2 |
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 { |