linux-kernel - Re: perf: fuzzer triggers NULL pointer derefreence in x86_schedule

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.11.1505080022340.26907@vincent-weaver-1.umelst.maine.edu>
Date:	Fri, 8 May 2015 00:25:50 -0400 (EDT)
From:	Vince Weaver <vincent.weaver@...ne.edu>
To:	Peter Zijlstra <peterz@...radead.org>
cc:	Stephane Eranian <eranian@...gle.com>,
	Vince Weaver <vincent.weaver@...ne.edu>,
	LKML <linux-kernel@...r.kernel.org>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Jiri Olsa <jolsa@...hat.com>, Ingo Molnar <mingo@...hat.com>,
	Paul Mackerras <paulus@...ba.org>
Subject: Re: perf: fuzzer triggers NULL pointer derefreence in
 x86_schedule_events

On Thu, 7 May 2015, Peter Zijlstra wrote:

> Indeed so; and we can make an analogous argument for hwc. However:
> 
> > I think it is more likely related to the bitmask (idxmsk).  But then
> > it is always allocated with the constraint even with the HT bug
> > workaround.  So most, likely the index is bogus and you touch outside
> > the idxmsk[] array.
> 
> [428232.701319] BUG: unable to handle kernel NULL pointer dereference at           (null)
> 
> But the thing really tried to touch NULL, not some random address that
> faulted.
> 
> As always, Vince has found us a good puzzle ;-)

and sorry I haven't been much help tracking it down.  I'm trying to 
trigger it again, but this particular bug only pops up after a week or so 
of fuzzing.  

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