Re: [PATCH 08/10] um: Fix possible race on task->mm

From: Richard Weinberger
Date: Sat Mar 24 2012 - 07:12:53 EST


Am 24.03.2012 11:30, schrieb Anton Vorontsov:
> Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
> assigns NULL under task_lock(), so tasklist lock is not enough).
>
> We can't use get_task_mm()/mmput() pair as mmput() might sleep,
> so let's take the task lock while we care about its mm.
>
> Note that we should also use find_lock_task_mm() to check all process'
> threads for a valid mm, but for uml we'll do it in a separate patch.
>
> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>

Acked-by: Richard Weinberger <richard@xxxxxx>

Thanks,
//richard

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