Kernel threads inherit CPU affinity from random sibling

Attilio Rao attilio at
Sat Jan 28 13:22:17 UTC 2012

2012/1/28 Ryan Stone <rysto32 at>:
> On Fri, Jan 27, 2012 at 10:41 PM, Attilio Rao <attilio at> wrote:
>> I think what you found out is very sensitive.
>> However, the patch is not correct as you cannot call
>> cpuset_setthread() with thread_lock held.
> Whoops!  I actually discovered that for myself and had already fixed
> it, but apparently I included an old version of the patch in the
> email.
>> Hence this is my fix:
> Oh, I do like this better.  I tried something similar myself but
> abandoned it because I misread how sched_affinity() was implemented by
> 4BSD(I had gotten the impression that once TSF_AFFINITY is set it
> could never be cleared).

Do you have a pathological test-case for it? Are you going to test the patch?


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