Re: [patch] Fixed the race that was oopsing Linux-2.2.0

Andrea Arcangeli (andrea@e-mind.com)
Wed, 27 Jan 1999 11:58:34 +0100 (CET)


On Wed, 27 Jan 1999, Andrea Arcangeli wrote:

> The other problem that was harming all people is that mmget() was
> incrasing the counter unconditionally. But it could increase it even if it
> was just 0. So we could have an mm with count 1 (increased by /proc), but

Before somebody will notice this: my fix is not the right one (probably
due lack to sleep ;). Incidentally it worked _fine_ because the race is so
fast that the slab cache had not the time to reuse the mm_struct (the one
where I hold the mm_lock even if it's just deallocated) for another task.

I am fixing it right this time. The fix is to make atomic the tsk->mm =
&init_mm and the mmput.

A real fix is coming soon...

Andrea Arcangeli

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