diff options
author | Gustavo A. R. Silva | 2020-03-09 13:10:08 -0500 |
---|---|---|
committer | Jaegeuk Kim | 2020-03-22 21:16:29 -0700 |
commit | 50b1203d8c9c057558341cf02c0df66ba99a7877 (patch) | |
tree | af0ab6bd3a7a5b004b01fac84392713848174250 | |
parent | a4ba5dfc5c88e49bb03385abfdd28c5a0acfbb54 (diff) |
f2fs: xattr.h: 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>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
-rw-r--r-- | fs/f2fs/xattr.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h index 0153b4c9ef21..e471be77f8f0 100644 --- a/fs/f2fs/xattr.h +++ b/fs/f2fs/xattr.h @@ -49,7 +49,7 @@ struct f2fs_xattr_entry { __u8 e_name_index; __u8 e_name_len; __le16 e_value_size; /* size of attribute value */ - char e_name[0]; /* attribute name */ + char e_name[]; /* attribute name */ }; #define XATTR_HDR(ptr) ((struct f2fs_xattr_header *)(ptr)) |