lkml.org 
[lkml]   [2007]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: compat_sys_times() bogus until jiffies >= 0.
> On Thu, 8 Nov 2007 12:53:57 +1100 Paul Mackerras <paulus@samba.org> wrote:
> Andrew Morton writes:
>
> > Given all this stuff, the return value from sys_times() doesn't seem a
> > particularly useful or reliable kernel interface.
>
> I think the best thing would be to ignore any error from copy_to_user
> and always return the number of clock ticks. We should call
> force_successful_syscall_return, and glibc on x86 should be taught not
> to interpret negative values as an error.

Changing glibc might be hard ;)

> POSIX doesn't require us to return an EFAULT error if the buf argument
> is bogus. If userspace does supply a bogus buf pointer, then either
> it will dereference it itself and get a segfault, or it won't
> dereference it, in which case it obviously didn't care about the
> values we tried to put there.
>
> If we try to return an error under some circumstances, then there is
> at least one 32-bit value for the number of ticks that will cause
> confusion. We can either change that value (or values) to some other
> value, which seems pretty bogus, or we can just decide not to return
> any errors. The latter seems to me to have no significant downside
> and to be the simplest solution to the problem.

"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.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-11-08 04:11    [W:0.727 / U:1.592 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site