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@xxxxxxxxxxxxxx>
---
drivers/net/usb/r8152.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index feedc0f964d8..9adfa2bbf593 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -891,7 +891,7 @@ struct fw_block {
struct fw_header {
u8 checksum[32];
char version[RTL_VER_SIZE];
- struct fw_block blocks[0];
+ struct fw_block blocks[];
} __packed;
/**
@@ -930,7 +930,7 @@ struct fw_mac {
__le32 reserved;
__le16 fw_ver_reg;
u8 fw_ver_data;
- char info[0];
+ char info[];
} __packed;
/**
@@ -982,7 +982,7 @@ struct fw_phy_nc {
__le16 bp_start;
__le16 bp_num;
__le16 bp[4];
- char info[0];
+ char info[];
} __packed;
enum rtl_fw_type {
--
2.25.0
