>
> The patch titled
> mm/mempolicy.c: add rcu read lock to protect pid structure
> has been removed from the -mm tree. Its filename was
> mm-mempolicyc-add-rcu-read-lock-to-protect-pid-structure.patch
>
> This patch was dropped because it was merged into mainline or a subsystem tree
>
> The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
>
> ------------------------------------------------------
> Subject: mm/mempolicy.c: add rcu read lock to protect pid structure
> From: Zeng Zhaoming <[email protected]>
>
> find_task_by_vpid() should be protected by rcu_read_lock(), to prevent
> free_pid() reclaiming pid.
>
> Signed-off-by: Zeng Zhaoming <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: KOSAKI Motohiro <[email protected]>
> Cc: Christoph Lameter <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
Andrew, please consider pick following patch too.
===========================================================================
>From 9de9f70f74e55d92b5e9057e22fc629405f63295 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <[email protected]>
Date: Thu, 16 Dec 2010 17:49:23 +0900
Subject: [PATCH] mempolicy: remove tasklist_lock from migrate_pages
Today, tasklist_lock in migrate_pages doesn't protect anything.
rcu_read_lock() provide enough protection from pid hash walk.
Reported-by: Peter Zijlstra <[email protected]>
Cc: Christoph Lameter <[email protected]>
Signed-off-by: KOSAKI Motohiro <[email protected]>
---
mm/mempolicy.c | 3 ---
1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 11ff260..9064945 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1308,16 +1308,13 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
/* Find the mm_struct */
rcu_read_lock();
- read_lock(&tasklist_lock);
task = pid ? find_task_by_vpid(pid) : current;
if (!task) {
- read_unlock(&tasklist_lock);
rcu_read_unlock();
err = -ESRCH;
goto out;
}
mm = get_task_mm(task);
- read_unlock(&tasklist_lock);
rcu_read_unlock();
err = -EINVAL;
--
1.6.5.2