Re: compat_sys_times() bogus until jiffies >= 0.

From: Andrew Morton
Date: Thu Nov 08 2007 - 00:20:45 EST


> On Thu, 8 Nov 2007 15:59:12 +1100 Paul Mackerras <paulus@xxxxxxxxx> wrote:
> Andrew Morton writes:
>
> > "the latter" is what my protopatch does isn't it? It wraps at 0x7fffffff.
> > It appears that glibc treats all of 0x80000000-0xffffffff as an error.
>
> Not on powerpc. On powerpc the error indication is carried separately
> in a condition register bit. So a force_successful_syscall_return()
> call will make glibc automatically do the right thing without any
> glibc changes on powerpc.

OK

> Wrapping at 0x7fffffff will cause programs to see large negative
> deltas between successive calls when the wrap occurs. I can see that
> giving userspace fits. :)
>

Yup. But userspace will already have a fit if either the start or end time
advanced into the glibc-thought-that-was-an-error range.

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