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SubjectRe: [GIT PULL] perf fixes
On Mon, Feb 22, 2010 at 09:01:39AM -0800, Linus Torvalds wrote:
>
>
> On Mon, 22 Feb 2010, Ingo Molnar wrote:
> >
> > The reason i'm sending them post -rc8 is the fix for the Wine breakage from
> > Frederic, which would be nice to see resolved in -final.
>
> Umm. That commit seems to be crap.
>
> Yes, it was wrong to not allow a NULL address breakpoint. But if you call
> kallsyms_lookup_name(), you should check the "I couldn't find it" end
> result for _that_ case, and 0 is the correct check there.
>
> So the code _should_ do something like
>
> if (info->name) {
> info->address = kallsyms_lookup_name(info->name);
> if (!info->address)
> return -EINVAL;
> }
>
> and that would correctly handle both the NULL original address _and_ the
> name lookup failure.



Ah you're right. That part in itself is buggy. Fortunately this won't ever
be reached because we don't use the info->name field anymore . It's a field I
forgot to remove when I re-adapted the new hw-breakpoint API on top of perf.
The name resolution (used by the ksym tracer and the hw-breakpoint sample
only) is done in an upper layer now, and never stored in the arch back end in any
case.

I'll remove this field and the associated dead-code for .34

Thanks.



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