Re: [PATCH 01/17] kbuild: Disable -Waddress-of-packed-member for gcc 9

From: Andi Kleen
Date: Fri Mar 22 2019 - 12:58:29 EST


> Lol... we're actively moving away from the C standard on many places.

Yes and also packed is not part of the C standard.

> Why does the silly compiler think it is a problem to take the address of
> a member of a packed structure? That sounds like something that's
> perfectly fine and useful.

Probably because a pointer reference doesn't do whatever magic
may be needed on architectures with poor misalignment handling.
In theory you would need memcpy().

In practice it's likely a lot of false positives, like
the architectures with poor misalignment handling are usually
in SOCs without PCI and they don't have the devices
with the problematic drivers.

-Andi