[RESEND PATCH v2 1/4] mm/hwpoison: fix traverse hugetlbfs page to avoid printk flood

From: Wanpeng Li
Date: Sat Sep 14 2013 - 19:55:04 EST


madvise_hwpoison won't check if the page is small page or huge page and traverse
in small page granularity against the range unconditional, which result in a printk
flood "MCE xxx: already hardware poisoned" if the page is huge page. This patch fix
it by increase 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;
}

Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 6975bc8..539eeb9 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);
--
1.8.1.2

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