Commit 1668bfd5 authored by Wu Fengguang's avatar Wu Fengguang Committed by Andi Kleen
Browse files

HWPOISON: abort on failed unmap 



Don't try to isolate a still mapped page. Otherwise we will hit the
BUG_ON(page_mapped(page)) in __remove_from_page_cache().

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
parent 82ba011b

mm/memory-failure.c

+15 −5
Original line number Diff line number Diff line
@@ -655,7 +655,7 @@ static int page_action(struct page_state *ps, struct page *p, 
 * Do all that is necessary to remove user space mappings. Unmap

 * the pages and send SIGBUS to the processes if the data was dirty.

 */

static void hwpoison_user_mappings(struct page *p, unsigned long pfn,

static int hwpoison_user_mappings(struct page *p, unsigned long pfn,

				  int trapno)

{

	enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
@@ -665,15 +665,18 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn, 
	int i;

	int kill = 1;



	if (PageReserved(p) || PageCompound(p) || PageSlab(p) || PageKsm(p))

		return;

	if (PageReserved(p) || PageSlab(p))

		return SWAP_SUCCESS;



	/*

	 * This check implies we don't kill processes if their pages

	 * are in the swap cache early. Those are always late kills.

	 */

	if (!page_mapped(p))

		return;

		return SWAP_SUCCESS;



	if (PageCompound(p) || PageKsm(p))

		return SWAP_FAIL;



	if (PageSwapCache(p)) {

		printk(KERN_ERR
@@ -735,6 +738,8 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn, 
	 */

	kill_procs_ao(&tokill, !!PageDirty(p), trapno,

		      ret != SWAP_SUCCESS, pfn);



	return ret;

}



int __memory_failure(unsigned long pfn, int trapno, int flags)
@@ -807,8 +812,13 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) 


	/*

	 * Now take care of user space mappings.

	 * Abort on fail: __remove_from_page_cache() assumes unmapped page.

	 */

	hwpoison_user_mappings(p, pfn, trapno);

	if (hwpoison_user_mappings(p, pfn, trapno) != SWAP_SUCCESS) {

		printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);

		res = -EBUSY;

		goto out;

	}



	/*

	 * Torn down by someone else?