From: Andrew Morton <akpm@linux-foundation.org>
Date: Sat, 5 Jul 2008 19:29:05 +0000 (-0700)
Subject: Fix clear_refs_write() use of struct mm_walk
X-Git-Tag: v2.6.26-rc9~5
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;ds=sidebyside;h=20cbc972617069c1ed434f62151e4de57d26ea46;p=linux-2.6-omap-h63xx.git

Fix clear_refs_write() use of struct mm_walk

Don't use a static entry, so as to prevent races during concurrent use
of this function.

Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ab8ccc9d14f..05053d701ac 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -476,10 +476,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		return -ESRCH;
 	mm = get_task_mm(task);
 	if (mm) {
-		static struct mm_walk clear_refs_walk;
-		memset(&clear_refs_walk, 0, sizeof(clear_refs_walk));
-		clear_refs_walk.pmd_entry = clear_refs_pte_range;
-		clear_refs_walk.mm = mm;
+		struct mm_walk clear_refs_walk = {
+			.pmd_entry = clear_refs_pte_range,
+			.mm = mm,
+		};
 		down_read(&mm->mmap_sem);
 		for (vma = mm->mmap; vma; vma = vma->vm_next) {
 			clear_refs_walk.private = vma;