Re: [PATCH] Cpuset: oops in exit on null cpuset fix

[Paul Jackson <pj@sgi.com>]

Andrew wrote:
> Seems strange to patch the kernel for this.  Can't the add-on patch do it? 
> Or can we just move the cpuset_exit()s to later in the exit() paths?

Sure, the add-on could have handled it, or had its exit routine
called earlier, or had cpuset_exit called later, ...

But it would still have been an accident waiting to happen again,
when someone adds another hook, or gets the order in cpuset_exit
wrong, or some such.

Heck, for all I know, your *-mm kernel might even have such a
bug now (before you took this patch).  Perhaps there was some
code path that would try to allocate memory after the cpuset_exit
call, and no one has hit on that path yet.

This patch was a zero runtime cost way to reduce the risks.  With
this patch, a task doesn't have a blackout period, shortly before
exit, when memory allocations will oops the kernel.

-- 
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                  Paul Jackson <pj@sgi.com> 1.925.600.0401