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    SubjectRe: [PATCH][next] net: sock_reuseport: Replace zero-length array with flexible-array member
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    From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
    Date: Fri, 28 Feb 2020 18:11:02 -0600

    > 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>

    Applied.

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