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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-09 13:04:41 -0500
committerJan Kara <jack@suse.cz>2020-03-16 15:56:50 +0100
commitc2d0699c629d30dde3329003baac3b94f1d717e6 (patch)
treea3a78a8dd1500be5ece761a94411f2435cd8f189
parentbc36dfffd5f3f19edcf85954d93eb0bc45875c37 (diff)
ext2: 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") Link: https://lore.kernel.org/r/20200309180441.GA2992@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/ext2/xattr.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext2/xattr.h b/fs/ext2/xattr.h
index cee888cdc235..16272e6ddcf4 100644
--- a/fs/ext2/xattr.h
+++ b/fs/ext2/xattr.h
@@ -39,7 +39,7 @@ struct ext2_xattr_entry {
__le32 e_value_block; /* disk block attribute is stored on (n/i) */
__le32 e_value_size; /* size of attribute value */
__le32 e_hash; /* hash value of name and value */
- char e_name[0]; /* attribute name */
+ char e_name[]; /* attribute name */
};
#define EXT2_XATTR_PAD_BITS 2