Messages in this thread | | | Date | Sat, 1 Feb 2014 17:06:53 -0800 | Subject | Re: [PATCH] Make math_state_restore() save and restore the interrupt flag | From | Suresh Siddha <> |
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On Sat, Feb 1, 2014 at 11:27 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > That said, regardless of the allocation issue, I do think that it's > stupid for kernel_fpu_{begin,end} to save the math state if > "used_math" was not set. So I do think__kernel_fpu_end() as-s is > buggy and stupid.
For eager_fpu case, assumption was every task should always have 'used_math' set. But i think there is a race, where we drop the fpu explicitly by doing drop_fpu() and meanwhile if we get an interrupt etc that ends up using fpu?
so I will Ack for option "b", as option "a" breaks the features which don't take into account cr0.TS.
Meanwhile I have the patch removing the delayed dynamic allocation for non-eager fpu. will post it after some testing.
thanks, suresh
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