[OpenAFS] OpenAFS client crashes on RHEL 5.10 and RHEL 6.5

[Renata Maria Dart]

Hi Andrew, we opened a ticket with RedHat, but it is
not clear how to proceed....are you thinking that we 
should be asking them for a fix? 

Thanks,

Renata


On Fri, 7 Mar 2014, Andrew Deason wrote:

>It has been discovered that the OpenAFS client interacts poorly with a
>change to the Linux kernel introduced in Red Hat Enterprise Linux
>versions 5.10 and 6.5, which can cause a kernel panic with certain AFS
>access patterns. Sites may want to exercise caution when considering
>upgrading RHEL systems that are running OpenAFS clients.
>
>While the mechanism that is causing this problem is understood and a
>solution is being developed, fixing this issue is not straightforward
>and may take some time. In the meantime, without a fix in place, the
>following workarounds may help avoid encountering the issue:
>
> - Avoid using multiple different mountpoints to access the same data,
>   since this can confuse the Linux VFS in some situations. This may be
>   difficult to guarantee (since /afs/cellname and /afs/.cellname
>   usually exist), but it may be possible to reduce such mountpoint
>   usage in some scenarios.
> 
> - Avoid running the RHEL 5.10 kernel or the RHEL 6.5 kernel on machines
>   with OpenAFS clients. However, these kernel updates contain stability
>   and security fixes, so it may not be desirable to avoid upgrading
>   such machines running OpenAFS clients.
>
>Note that the RHEL 7 Beta is not affected by this issue, but it is not
>known if the final release of RHEL 7 will. No other distributions of
>Linux are known to be affected by this (except any that are derived from
>RHEL), and the problematic change to the Linux kernel is not in vanilla
>upstream Linux kernel releases.
>
>If your site has a support contract with Red Hat, you may wish to
>inquire about this issue through your support channel. For reference,
>the issue was introduced in RHEL5 in kernel 2.6.18-367.el5 with this
>change:
>
> - [fs] vfs: stop d_splice_alias creating directory aliases (J. Bruce Fields) [785916]
>
>and in RHEL6 in kernel 2.6.32-408.el6 with this change:
>
> - [fs] vfs: stop d_splice_alias creating directory aliases (J. Bruce Fields) [820446]
>
>For more details and future updates on this issue, see this RT ticket:
><https://rt.central.org/rt/Ticket/Display.html?id=130273&user=guest&pass=guest>
>
>-- 
>Andrew Deason
>adeason@sinenomine.net
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