Date: Wed, 9 Oct 2013 21:02:31 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>, Fengguang Wu <fengguang.wu@intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Richard Henderson <rth@twiddle.net>
Subject: Re: [x86] BUG: unable to handle kernel paging request at 00740060
Message-ID: <20131009190231.GI13848@laptop.programming.kicks-ass.net>
References: <20131005234430.GA22485@localhost>
 <CA+55aFxEeKixnH7mZZs5iwupA9_GsRN0N7QZxqcTcE4RKZvTTg@mail.gmail.com>
 <20131008143400.GA14721@redhat.com>
 <20131009080459.GA2298@localhost>
 <20131009124310.GA11769@redhat.com>
 <20131009140734.GH3081@twins.programming.kicks-ass.net>
 <20131009143359.GU26785@twins.programming.kicks-ass.net>
 <20131009144656.GV26785@twins.programming.kicks-ass.net>
 <20131009181613.GW30970@tucnak.zalov.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20131009181613.GW30970@tucnak.zalov.cz>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 782
Lines: 15

On Wed, Oct 09, 2013 at 08:16:13PM +0200, Jakub Jelinek wrote:
> Confirmed as gcc bug, filed http://gcc.gnu.org/PR58670
> Seems all of 4.[6-9] miscompile it.  Will have a look tomorrow
> unless somebody beats me to it.  But historically, the case where
> asm goto labels jump to fallthru basic block had numerous problems in the
> past.

That bug lists the component as middle end; this suggests x86_64 would
be vulnerable too, can you confirm? So far we've only observed the wrong
code on i386 targets, x86_64 targets appeared correct.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/