3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
commit 783657a7dc20e5c0efbc9a09a9dd38e238a723da upstream.
When we try to soft-offline a thp tail page, put_page() is called on the
tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page().
This patch splits thp before going into the main body of soft-offlining.
Signed-off-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
Cc: Andi Kleen <a...@firstfloor.org>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Andi Kleen <andi.kl...@intel.com>
Cc: Wu Fengguang <fengguang...@intel.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
mm/memory-failure.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 6c5899b..8b20278 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1476,9 +1476,17 @@ int soft_offline_page(struct page *page, int flags)
{
int ret;
unsigned long pfn = page_to_pfn(page);
+ struct page *hpage = compound_trans_head(page);
if (PageHuge(page))
return soft_offline_huge_page(page, flags);
+ if (PageTransHuge(hpage)) {
+ if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
+ pr_info("soft offline: %#lx: failed to split THP\n",
+ pfn);
+ return -EBUSY;
+ }
+ }
ret = get_any_page(page, pfn, flags);
if (ret < 0)
--
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