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

From: [email-masked] (Richard Weinberger)
Date: Sat, 24 Mar 2012 12:12:12 +0100

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 <[email-masked]>

Acked-by: Richard Weinberger <[email-masked]>

Thanks,
//richard

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