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SubjectRE: [PATCH] PCI: hv: Replace zero-length array with flexible-array member
> From:
> <> On Behalf Of Gustavo A. R. Silva
> Sent: Wednesday, February 12, 2020 4:51 PM
> ...
> 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.

Looks good to me. Thanks, Gustavo!

Reviewed-by: Dexuan Cui <>

FWIW, it looks there are a lot of more to fix in the kernel tree: the below
commands return 1373 for me:

grep -nr '\[0\];$' * | grep '\.h:' | grep -v = | wc -l

Running the commands against the kernel/ directory returns 3.

-- Dexuan

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