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")
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| @@ -83,7 +83,7 @@ struct wilco_ec_response { · 82 unmodified lines | ||
| 83 | 83 | u16 result; |
| 84 | 84 | u16 data_size; |
| 85 | 85 | u8 reserved[2]; |
| 86 | − u8 data[0]; | |
| 86 | + u8 data[]; | |
| 87 | 87 | } __packed; |
| 88 | 88 | |
| 89 | 89 | /** |