[rhelv6-list] A kernel bug that causes a system crash when the uptime is longer than 208.5 days

[Robin Price II]

Bugzilla:  https://bugzilla.redhat.com/show_bug.cgi?id=765720

This is private due to private information from customer use cases.  If 
you need further details, I would highly encourage you to contact Red 
Hat support or your TAM.

Here is the initial information opened in the BZ:

"The following patch is in urgent fix for Linus branch, which avoid the
unnecessary overflow in sched_clock otherwise kernel will crash after 
209~250 days.

http://git.kernel.org/?p=linux/kernel/git/tip/tip.git;a=patch;h=4cecf6d401a01d054afc1e5f605bcbfe553cb9b9

In hundreds of days, the __cycles_2_ns calculation in sched_clock
has an overflow.  cyc * per_cpu(cyc2ns, cpu) exceeds 64 bits, causing 
the final value to become zero.  We can solve this without losing any 
precision. We can decompose TSC into quotient and remainder of division 
by the scale factor, and then use this to convert TSC into nanoseconds."

~rp

On 01/06/2012 11:18 AM, Akemi Yagi wrote:
> Hi,
>
> There is a kernel bug that causes a system crash when the uptime goes
> over 208.5 days. According to available info, the patch [1] is now in
> kernel 3.1.5. RHEL 6 is apparently affected (timer.h has the buggy
> code). I was not able to find a bug report at bugzilla.redhat.com that
> is seemingly related to this bug but my search is not extensive.
>
> Is there anyone running the RHEL-6 system long enough to see this bug?
>
> Akemi
>
> [1] http://www.google.com/url?sa=D&q=http://git.kernel.org/%3Fp%3Dlinux/kernel/git/tip/tip.git%3Ba%3Dcommitdiff%3Bh%3D4cecf6d401a01d054afc1e5f605bcbfe553cb9b9&usg=AFQjCNFaSQTxnRMEckhXsYkZlRloks3WJg
>
> _______________________________________________
> rhelv6-list mailing list
> rhelv6-list at redhat.com
> https://www.redhat.com/mailman/listinfo/rhelv6-list


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| Robin Price II - RHCE,RHCDS,RHCVA                   |
| Solutions Architect                                 |
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