From: Paul Jackson <pj@sgi.com>
Date: Fri, 31 Mar 2006 10:30:51 +0000 (-0800)
Subject: [PATCH] cpuset: unsafe mm reference fix
X-Git-Tag: v2.6.17-rc1~83
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2741a559a01e1ba9bf87285569dc1a104d134ecf;p=linux-2.6

[PATCH] cpuset: unsafe mm reference fix

Fix unsafe reference to a tasks mm struct, by moving the reference inside of a
convenient nearby properly guarded code block.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 2523a4b6a8..bf42381a41 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1183,11 +1183,11 @@ static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
 	mm = get_task_mm(tsk);
 	if (mm) {
 		mpol_rebind_mm(mm, &to);
+		if (is_memory_migrate(cs))
+			do_migrate_pages(mm, &from, &to, MPOL_MF_MOVE_ALL);
 		mmput(mm);
 	}
 
-	if (is_memory_migrate(cs))
-		do_migrate_pages(tsk->mm, &from, &to, MPOL_MF_MOVE_ALL);
 	put_task_struct(tsk);
 	synchronize_rcu();
 	if (atomic_dec_and_test(&oldcs->count))