Re: [GIT PULL] perf fixes

From: Linus Torvalds
Date: Mon Feb 22 2010 - 12:02:14 EST




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.

Also, note how I removed the totally bogus cast.

Anyway, I pulled, but I really wish somebody had thought through those
cases. Somebody who knows the code better than I do (maybe there is an
error check later for "if (info->name && !info->address)", but I didn't
see one in a quick grep).

Linus
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