Infrequent heap corruption, XO-4, Fedora 20

[James Cameron]

Thanks.

Can I make it happen more often?

Is there a later version of the driver?

We have a different version that I may look into, on arm-3.5-android
branch.

On Wed, Feb 04, 2015 at 12:14:02PM +0100, Jon Nettleton wrote:
> It is a problem with the v4 version of the galcore driver.  We have replicated
> it on a couple of platforms.
> 
> On Wed, Feb 4, 2015 at 11:26 AM, Peter Robinson <[1]pbrobinson at gmail.com>
> wrote:
> 
>     On Wed, Feb 4, 2015 at 8:10 AM, James Cameron <[2]quozl at laptop.org> wrote:
>     > Following up a thread from last September.
>     >
>     > This problem has just become more interesting, because it hit during
>     > an activity startup.
>     >
>     > I'm quite used to seeing it with yum.  But seeing it without yum now
>     > points us at kernel, glibc or python.
> 
>     We've not seen this in the wider F-20 Fedora ARM distro so my bet
>     would be on the kernel.
> 
>     Peter
> 
>     > [3]http://dev.laptop.org/ticket/12837#comment:4 has the details of the
>     > most recent event.
>     >
>     > On Wed, Sep 10, 2014 at 01:56:27PM +1000, James Cameron wrote:
>     >> G'day Peter,
>     >>
>     >> Thanks for any ideas you may have.
>     >>
>     >> The problem also reproduces on OLPC Fedora 20 image for XO-4:
>     >>
>     >> [4]http://build.laptop.org/14.1.0/os1/xo-4/41001o4.zd (552 MB)
>     >>
>     >> *** Error in `/usr/bin/python': free(): invalid pointer: 0x047c79ae ***
>     >> ======= Backtrace: =========
>     >> /lib/libc.so.6(+0x6c8b4)[0xb6c828b4]
>     >> /lib/libc.so.6(+0x754e8)[0xb6c8b4e8]
>     >> ======= Memory map: ========
>     >> [...]
>     >>
>     >> The error varies in detail, but always suggests corruption of heap or
>     >> pointers to heap.
>     >>
>     >> The triggering conditions are interactive use of yum, yum update, or
>     >> yum used by olpc-os-builder.  The latter is a simple reproducer for me.
>     >>
>     >> I'm reproducing it on an XO-4, with 2GB of RAM, no swap, 8 GB eMMC, 8
>     >> GB USB flash drive.
>     >>
>     >> While memory demand by yum is large by comparison to other programs,
>     >> the available memory at the time of failure is ample.  There are no
>     >> kernel out of memory (OOM) events.  It seems more likely to occur when
>     >> the filesystem cache is under heavy demand.
>     >>
>     >> The method to recreate the problem was:
>     >>
>     >> 1.  install the system image 41001o4.zd using fs-update and then boot,
>     >>
>     >> 2.  configure wireless network,
>     >>
>     >> 3.  "yum install -y git olpc-os-builder"
>     >>
>     >> 4.  clone the master branch of
>     >> git://[5]dev.laptop.org/projects/olpc-os-builder
>     >> (last verified with b87e6ee)
>     >>
>     >> 5.  run "./osbuilder.py examples/olpc-os-14.1.0-xo4.ini" repeatedly
>     >> until the error occurs (usually within about five attempts),
>     >>
>     >>
>     >> I've also tried running under valgrind, but that causes illegal
>     >> instruction.  It is quite likely I'm not using valgrind correctly.
>     >> [6]http://dev.laptop.org/~quozl/z/1XRYtO.txt
>     >>
>     >> The workaround at the moment is to build our Fedora 20 images on
>     >> Fedora 18.  Fedora 18 shows no sign of the problem.  I'm worried that
>     >> a low probability heap corruptor may cause instability of applications
>     >> in the field.
>     >>
>     >> The exact same kernel is being used for Fedora 18 and Fedora 20.
>     >>
>     >> On Tue, Sep 09, 2014 at 03:55:24PM +0100, Peter Robinson wrote:
>     >> > What version of OOB are you using, and what config files? I can try
>     >> > and recreate the problem here on other devices.
>     >>
>     >> --
>     >> James Cameron
>     >> [7]http://quozl.linux.org.au/
>     >
>     > --
>     > James Cameron
>     > [8]http://quozl.linux.org.au/
>     _______________________________________________
>     Devel mailing list
>     [9]Devel at lists.laptop.org
>     [10]http://lists.laptop.org/listinfo/devel
> 
> References:
> 
> [1] mailto:pbrobinson at gmail.com
> [2] mailto:quozl at laptop.org
> [3] http://dev.laptop.org/ticket/12837#comment:4
> [4] http://build.laptop.org/14.1.0/os1/xo-4/41001o4.zd
> [5] http://dev.laptop.org/projects/olpc-os-builder
> [6] http://dev.laptop.org/~quozl/z/1XRYtO.txt
> [7] http://quozl.linux.org.au/
> [8] http://quozl.linux.org.au/
> [9] mailto:Devel at lists.laptop.org
> [10] http://lists.laptop.org/listinfo/devel

-- 
James Cameron
http://quozl.linux.org.au/