summaryrefslogtreecommitdiff
path: root/fs/ext4/namei.c
diff options
context:
space:
mode:
authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-13 10:06:48 -0600
committerTheodore Ts'o <tytso@mit.edu>2020-03-05 20:25:05 -0500
commit6cfb061fe9e901dd0b6cfa3ed50bc39c81523532 (patch)
tree8e0a230c5b32d3f5fa40a9679076ec6dc0b8838d /fs/ext4/namei.c
parent92e9c58c5629762001e7294afbdf1283d5c7d2ed (diff)
ext4: use flexible-array members in struct dx_node and struct dx_root
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> Link: https://lore.kernel.org/r/20200213160648.GA7054@embeddedor Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/namei.c')
-rw-r--r--fs/ext4/namei.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index b05ea72f38fd..5f0a758956f6 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -233,13 +233,13 @@ struct dx_root
u8 unused_flags;
}
info;
- struct dx_entry entries[0];
+ struct dx_entry entries[];
};
struct dx_node
{
struct fake_dirent fake;
- struct dx_entry entries[0];
+ struct dx_entry entries[];
};