[PATCH -tip v4 6/6] [RFC] kprobes/x86: Call exception handlers directly from do_int3/do_debug

[Jiri Kosina]

On Thu, 12 Dec 2013, Masami Hiramatsu wrote:

> > Yeah, it's broken. Obviously, if you happen to trigger int3 before the 
> > notifier has been registered, it'd cause int3 exception to be unhandled. 
> > See
> > 
> > 	commit 17f41571bb2c4a398785452ac2718a6c5d77180e
> > 	Author: Jiri Kosina <jkosina@suse.cz>
> > 	Date:   Tue Jul 23 10:09:28 2013 +0200
> > 
> > 	    kprobes/x86: Call out into INT3 handler directly instead of using notifier
> > 
> > for one such issue that happened with jump labels.
> > 
> >> Hmm, if there's no users of the int3 notifier, should we just remove it?
> > 
> > Hmm, there are still uprobes, right?
> 
> Right, uprobes still use it, however, since it only handles user-space
> breakpoint, there is no problem.

Agreed. But therefore the notifier can't just be removed, unless uprobes 
are converted to direct call as well (but I don't think that'd be 
beneficial, notifier is sufficient in this case).

-- 
Jiri Kosina
SUSE Labs