Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9893e49d authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
Browse files

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



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: default avatarAndi Kleen <ak@linux.intel.com>
parent f590f333

include/asm-generic/mman-common.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -34,6 +34,7 @@ 
#define MADV_REMOVE	9		/* remove these pages & resources */

#define MADV_REMOVE	9		/* remove these pages & resources */

#define MADV_DONTFORK	10		/* don't inherit across fork */

#define MADV_DONTFORK	10		/* don't inherit across fork */

#define MADV_DOFORK	11		/* do inherit across fork */

#define MADV_DOFORK	11		/* do inherit across fork */

#define MADV_HWPOISON	100		/* poison a page for testing */





/* compatibility flags */

/* compatibility flags */

#define MAP_FILE	0

#define MAP_FILE	0

mm/madvise.c

+30 −0
Original line number Original line Diff line number Diff line
@@ -207,6 +207,32 @@ static long madvise_remove(struct vm_area_struct *vma, 
	return error;

	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

static long

madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,

madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,

		unsigned long start, unsigned long end, int behavior)

		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;

	int write;

	size_t len;

	size_t len;





#ifdef CONFIG_MEMORY_FAILURE

	if (behavior == MADV_HWPOISON)

		return madvise_hwpoison(start, start+len_in);

#endif

	if (!madvise_behavior_valid(behavior))

	if (!madvise_behavior_valid(behavior))

		return error;

		return error;