From 20cb6cab52a21b46e3c0dc7bd23f004f810fb421 Mon Sep 17 00:00:00 2001
From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Date: Mon, 30 Sep 2013 13:45:21 -0700
Subject: [PATCH] mm/hwpoison: fix traversal of hugetlbfs pages to avoid printk
flood
madvise_hwpoison won't check if the page is small page or huge page and
traverses in small page granularity against the range unconditionally,
which result in a printk flood "MCE xxx: already hardware poisoned" if
the page is a huge page.
This patch fixes it by using compound_order(compound_head(page)) for
huge page iterator.
Testcase:
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <errno.h>
#define PAGES_TO_TEST 3
#define PAGE_SIZE 4096 * 512
int main(void)
{
char *mem;
int i;
mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,
PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, 0, 0);
if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1)
return -1;
munmap(mem, PAGES_TO_TEST * PAGE_SIZE);
return 0;
}
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/madvise.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/madvise.c b/mm/madvise.c
index 6975bc812542..539eeb96b323 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -343,10 +343,11 @@ static long madvise_remove(struct vm_area_struct *vma,
*/
static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
{
+ struct page *p;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- for (; start < end; start += PAGE_SIZE) {
- struct page *p;
+ for (; start < end; start += PAGE_SIZE <<
+ compound_order(compound_head(p))) {
int ret;
ret = get_user_pages_fast(start, 1, 0, &p);