Re: error: implicit declaration of function 'zero_bytemask'

From: Chris Metcalf
Date: Wed Oct 07 2015 - 09:29:44 EST


On 10/07/2015 08:53 AM, Michal Sojka wrote:
Dear Chris,

the following commit breaks my Linux build.

commit 990486c8af044f89bddfbde1d1cf9fde449bedbf
Author: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Date: Tue Oct 6 12:37:41 2015 -0400
strscpy: zero any trailing garbage bytes in the destination
It's possible that the destination can be shadowed in userspace
(as, for example, the perf buffers are now). So we should take
care not to leak data that could be inspected by userspace.

The error message is:

lib/string.c: In function 'strscpy':
lib/string.c:209:4: error: implicit declaration of function 'zero_bytemask' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors

I compile the kernel for PowerPC (32 bit) with the attached config.

Ah, it appears that big-endian powerpc does not provide
zero_bytemask(), only little-endian. I'll fix this in v3 of
the patch series - thanks!

--
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com

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