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: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 3338c44..b62287d 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -655,7 +655,7 @@
* 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 @@
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 @@
*/
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 @@
/*
* 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?