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-rw-r--r--mm/memory-failure.c21
1 files changed, 11 insertions, 10 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b25ed321e667..4f08a2d61487 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -856,14 +856,14 @@ static int page_action(struct page_state *ps, struct page *p,
* the pages and send SIGBUS to the processes if the data was dirty.
*/
static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
- int trapno, int flags)
+ int trapno, int flags, struct page **hpagep)
{
enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
struct address_space *mapping;
LIST_HEAD(tokill);
int ret;
int kill = 1, forcekill;
- struct page *hpage = compound_head(p);
+ struct page *hpage = *hpagep;
struct page *ppage;
if (PageReserved(p) || PageSlab(p))
@@ -942,11 +942,14 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* We pinned the head page for hwpoison handling,
* now we split the thp and we are interested in
* the hwpoisoned raw page, so move the refcount
- * to it.
+ * to it. Similarly, page lock is shifted.
*/
if (hpage != p) {
put_page(hpage);
get_page(p);
+ lock_page(p);
+ unlock_page(hpage);
+ *hpagep = p;
}
/* THP is split, so ppage should be the real poisoned page. */
ppage = p;
@@ -964,17 +967,11 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
if (kill)
collect_procs(ppage, &tokill);
- if (hpage != ppage)
- lock_page(ppage);
-
ret = try_to_unmap(ppage, ttu);
if (ret != SWAP_SUCCESS)
printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
pfn, page_mapcount(ppage));
- if (hpage != ppage)
- unlock_page(ppage);
-
/*
* Now that the dirty bit has been propagated to the
* struct page and all unmaps done we can decide if
@@ -1193,8 +1190,12 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
/*
* Now take care of user space mappings.
* Abort on fail: __delete_from_page_cache() assumes unmapped page.
+ *
+ * When the raw error page is thp tail page, hpage points to the raw
+ * page after thp split.
*/
- if (hwpoison_user_mappings(p, pfn, trapno, flags) != SWAP_SUCCESS) {
+ if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)
+ != SWAP_SUCCESS) {
printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);
res = -EBUSY;
goto out;