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HWPOISON: Use get_user_page_fast in hwpoison madvise

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The previous version didn't take the mmap_sem before calling gup(),
which is racy.

Use get_user_pages_fast() instead which doesn't need any locks.
This is also faster of course, but then it doesn't really matter
because this is just a testing path.

Based on report from Nick Piggin.
Cc: npiggin@suse.de

Signed-off-by: Andi Kleen <ak@linux.intel.com>
This commit is contained in:
Andi Kleen 2009-12-16 12:20:00 +01:00 committed by Andi Kleen
parent 1bfe5febe3
commit d15f107d97
1 changed files with 1 additions and 2 deletions
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3
mm/madvise.c
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@ -230,8 +230,7 @@ static int madvise_hwpoison(unsigned long start, unsigned long end)
return -EPERM;
for (; start < end; start += PAGE_SIZE) {
struct page *p;
int ret = get_user_pages(current, current->mm, start, 1,
0, 0, &p, NULL);
int ret = get_user_pages_fast(start, 1, 0, &p);
if (ret != 1)
return ret;
printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",