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HWPOISON: Add madvise() based injector for hardware poisoned pages v4

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Impact: optional, useful for debugging

Add a new madvice sub command to inject poison for some
pages in a process' address space.  This is useful for
testing the poison page handling.

This patch can allow root to tie up large amounts of memory.
I got feedback from container developers and they didn't see any
problem.

v2: Use write flag for get_user_pages to make sure to always get
a fresh page
v3: Don't request write mapping (Fengguang Wu)
v4: Move MADV_* number to avoid conflict with KSM (Hugh Dickins)

Signed-off-by: Andi Kleen <ak@linux.intel.com>
This commit is contained in:
Andi Kleen 2009-09-16 11:50:17 +02:00 committed by Andi Kleen
parent f590f333fb
commit 9893e49d64
2 changed files with 31 additions and 0 deletions
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1
include/asm-generic/mman-common.h
View file

@ -34,6 +34,7 @@
#define MADV_REMOVE 9 /* remove these pages & resources */
#define MADV_DONTFORK 10 /* don't inherit across fork */
#define MADV_DOFORK 11 /* do inherit across fork */
#define MADV_HWPOISON 100 /* poison a page for testing */
/* compatibility flags */
#define MAP_FILE 0

30
mm/madvise.c
View file

@ -207,6 +207,32 @@ static long madvise_remove(struct vm_area_struct *vma,
return error;
}
#ifdef CONFIG_MEMORY_FAILURE
/*
* Error injection support for memory error handling.
*/
static int madvise_hwpoison(unsigned long start, unsigned long end)
{
int ret = 0;
if (!capable(CAP_SYS_ADMIN))
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);
if (ret != 1)
return ret;
printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
page_to_pfn(p), start);
/* Ignore return value for now */
__memory_failure(page_to_pfn(p), 0, 1);
put_page(p);
}
return ret;
}
#endif
static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
unsigned long start, unsigned long end, int behavior)
@ -307,6 +333,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
int write;
size_t len;
#ifdef CONFIG_MEMORY_FAILURE
if (behavior == MADV_HWPOISON)
return madvise_hwpoison(start, start+len_in);
#endif
if (!madvise_behavior_valid(behavior))
return error;