linux-kernel - Re: [PATCH 1/1] Fix int1 recursion when no perf_bp

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]

Date:	Thu, 10 Dec 2015 21:49:33 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andy Lutomirski <luto@...capital.net>
cc:	Jeff Merkey <linux.mdb@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, X86 ML <x86@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Andy Lutomirski <luto@...nel.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Borislav Petkov <bp@...en8.de>, Jiri Olsa <jolsa@...nel.org>
Subject: Re: [PATCH 1/1] Fix int1 recursion when no perf_bp_event is
 registeredy

On Thu, 10 Dec 2015, Andy Lutomirski wrote:
> On brief inspection, this smells like a microcode bug.  Can you send
> /proc/cpuinfo output?
> 
> If this is the issue, I'm not sure we want to be in the business of
> working around localized microcode bugs and, if we do, then I think we
> should explicitly detect the bug and log about it.

I think we should handle such stuff gracefully. Yes, we should log it
and we also should check what the contents of the debug registers are.

If dr7 has a break point enabled w/o perf having one installed then we
know that someone did a horrible hackery ....

Thanks,

	tglx


--
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/