Re: [patch] preemptive kernel, preemptive-2.3.52-A7

From: Andrea Arcangeli (andrea@suse.de)
Date: Tue Mar 14 2000 - 12:48:38 EST


On Tue, 14 Mar 2000, Ingo Molnar wrote:

>no, we do not want to execute signal code in that context. I've
>intentionally avoided this. Think about it, the signal handler should not
>be executed now because the eg. interrupted memcpy() in the middle of an
>(otherwise uninterruptible) is not really intended to return to user-space
>anywhere. It does work technically to a certain degree, but jumping to
>ret_with_reschedule is just asking for trouble - unbounded kernel-stack
>recursion for example, and i think some security holes are possible as
>well.

Agreed.

>i havent seen any crash with preemptive-2.3.52-B7. (The only crashes i
>ever got were the controlled asserts in preempt_on(), checking for
>TASK_RUNNING.) [..]

Right, all the preemtable kernel code has to be definitely in
TASK_RUNNING.

Andrea

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