There is a race between madvise_hwpoison path and memory_failure:
CPU0 CPU1
madvise_hwpoison
get_user_pages_fast
PageHWPoison check (false)
memory_failure
TestSetPageHWPoison
soft_offline_page
PageHWPoison check (true)
return -EBUSY (without put_page)
Suggested-by: Naoya Horiguchi <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
---
mm/memory-failure.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 56b8a71..e0eb7ab 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1704,6 +1704,8 @@ int soft_offline_page(struct page *page, int flags)
if (PageHWPoison(page)) {
pr_info("soft offline: %#lx page already poisoned\n", pfn);
+ if (flags & MF_COUNT_INCREASED)
+ put_page(page);
return -EBUSY;
}
if (!PageHuge(page) && PageTransHuge(hpage)) {
--
1.7.1