Re: Fw: 2.5.61 oops running SDET

From: Linus Torvalds (torvalds@transmeta.com)
Date: Sun Feb 16 2003 - 14:17:11 EST


On Sun, 16 Feb 2003, Martin J. Bligh wrote:
>
> Well, I did the stupid safe thing, and it hangs the box once we get up to
> a load of 32 with SDET. Below is what I did, the only other issue I can
> see in here is that task_mem takes mm->mmap_sem which is now nested inside
> the task_lock inside tasklist_lock ... but I can't see anywhere that's a
> problem from a quick search

Ho - you can _never_ nest a semaphore inside a spinlock - if the semaphore
sleeps, the spinlock will cause a lockup regardless of any reverse nesting
issues.. So I guess the old "get_task_mm()" code is requried anyway.

                Linus

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