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Date: Wed, 18 Mar 2015 21:50:27 +0300
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrey Wagin <avagin@gmail.com>, Andy Lutomirski <luto@kernel.org>,
        Ingo Molnar <mingo@kernel.org>, Andi Kleen <andi@firstfloor.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Al Viro <viro@zeniv.linux.org.uk>,
        X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@amacapital.net>,
        Pavel Emelyanov <xemul@openvz.org>
Subject: Re: [PATCH v3 1/2] x86_64,signal: Fix SS handling for signals
 delivered to 64-bit programs
Message-ID: <20150318185027.GB17491@moon>
References: <cover.1426193719.git.luto@kernel.org>
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On Wed, Mar 18, 2015 at 07:31:33PM +0100, Oleg Nesterov wrote:
> On 03/18, Cyrill Gorcunov wrote:
> >
> > On Wed, Mar 18, 2015 at 06:48:43PM +0100, Oleg Nesterov wrote:
> > >
> > > Shot in a dark afer a quick grep: restore_gpregs() should initialize ->ss?
> >
> > It hasn't been needed earlier, if this would help it means abi is broken, no? :)
> > Otherwise I don't understand what's happening.
> 
> until this commit the kernel simply forgot to restore ->ss in sigreturn().
> 
> after this commit, if your rt_sigframe has garbage in ->ss then SIGSEGV
> is clear.

OK, so setting up a proper ss here should fix problem.

> > >
> > > Seriously, where is UserX86RegsEntry?
> >
> > It's in protobif/core-x86.proto, welcome to protobuf hell.
> 
> Still can't find UserX86RegsEntry... OK, perhaps it comes from
> user_x86_regs_entry in protobuf/core-x86.proto. Then I guess the patch I sent
> can be compiled at least ;)

Yeah, protobuf-c mangles "_" in message name so user_x86_regs_entry -> UserX86RegsEntry.
Andrew should be able to test it tomorrow (hopefully it's no urgent right? ;)