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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-23 18:00:04 -0500 |
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committer | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-04-18 15:44:55 -0500 |
commit | 1d9e13e8ef05029c61d52ad9a6f48f14771d14b7 (patch) | |
tree | 577956858e224710ecfa68669d1be1d36b1acb8c | |
parent | 0ead33642f1df89699f2e4dda8eea59c326b68f6 (diff) | |
download | linux-1d9e13e8ef05029c61d52ad9a6f48f14771d14b7.tar.bz2 |
ihex.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>
-rw-r--r-- | include/linux/ihex.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ihex.h b/include/linux/ihex.h index 98cb5ce0b0a0..b824877e6d1b 100644 --- a/include/linux/ihex.h +++ b/include/linux/ihex.h @@ -18,7 +18,7 @@ struct ihex_binrec { __be32 addr; __be16 len; - uint8_t data[0]; + uint8_t data[]; } __attribute__((packed)); static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p) |