Re: [RFC][PATCH] fix move/migrate_pages() race on task struct

On 02/24/2012 07:20 AM, Christoph Lameter wrote:

Subject: migration: Do not do rcu_read_unlock until the last time we need the task_struct pointer

Migration functions perform the rcu_read_unlock too early. As a result the
task pointed to may change. Bugs were introduced when adding security checks
because rcu_unlock/lock sequences were inserted. Plus the security checks
and do_move_pages used the task_struct pointer after rcu_unlock.

Fix those issues by removing the unlock/lock sequences and moving the
rcu_read_unlock after the last use of the task struct pointer.

Signed-off-by: Christoph Lameter <redacted>

It doesn't fix the code duplication, but it definitely does fix the bug
I was originally trying to address.

Acked-by: Dave Hansen <redacted>

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