linux-kernel - Re: [PATCH 4.4 00/37] 4.4.110-stable review

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: <AA8653C7-EA47-4651-AE51-FCBF2ABFBBD8@amacapital.net>
Date:   Thu, 4 Jan 2018 12:43:41 -0800
From:   Andy Lutomirski <luto@...capital.net>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Thomas Voegtle <tv@...96.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Shuah Khan <shuahkh@....samsung.com>, patches@...nelci.org,
        Ben Hutchings <ben.hutchings@...ethink.co.uk>,
        lkft-triage@...ts.linaro.org, stable <stable@...r.kernel.org>
Subject: Re: [PATCH 4.4 00/37] 4.4.110-stable review


> On Jan 4, 2018, at 12:29 PM, Linus Torvalds <torvalds@...ux-foundation.org> wrote:
> 
>> On Thu, Jan 4, 2018 at 12:16 PM, Thomas Voegtle <tv@...96.de> wrote:
>> 
>> Attached a screenshot.
>> Is that useful? Are there some debug options I can add?
> 
> Not much of an oops, because the SIGSEGV happens in user space. The
> only reason you get any kernel stack printout at all is because 'init'
> dying will make the kernel print that out.
> 
> The segfault address for init looks like the fixmap area to me (first
> byte in the last page of the fixmap?). "Error 5" means that it's a
> user-space read that got a protection fault. So it's not a LDT of GDT
> update or anything like that, it's a normal access from user space (or
> a qemu emulation bug, but that sounds unlikely).
> 
> Is that the vsyscall page?
> 
> Adding Luto to the participants. I think he noticed one of the
> vsyscall patches missing earlier in the 4.9 series. Maybe the 4.4
> series had something similar..
> 

That's almost certainly it.

I'll try to find some time today or tomorrow to add a proper selftest.

>              Linus