Messages in this thread | | | Date | Wed, 26 Jan 2000 01:48:43 +0100 (CET) | From | Rik van Riel <> | Subject | Re: 2.2.1{3,4,5pre*} VM bug found |
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On Tue, 25 Jan 2000, Andrea Arcangeli wrote:
> Before calling schedule() you always gets registered in a > waitqueue so you can't deadlock or wait too much. > > If something there is the opposite problem. If you do: > > __set_current_state(TASK_UNINTERRUPTIBLE); > get_page(GFP_KERNEL); > XXXXXXXXXXXXXXXXXXXX > schedule(); > > then at point XXXXXXX you may become a task running and you don't > block anymore.
The problem in this case is that schedule() may be called from within get_page(GFP_KERNEL). This already was possible in 2.2.14 and before (if the task had to wait for I/O on try_to_free_pages()), but the explicit schedule() in my stuff in 2.2.15pre4 amplified the problem and made it visible.
A fix for this problem is in one of my other emails and at my web page: http://www.surriel.com/patches/
regards,
Rik -- The Internet is not a network of computers. It is a network of people. That is its real strength.
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