On 12.01.21 10:34, Dan Williams wrote:
The conversion to move pfn_to_online_page() internal to soft_offline_page() missed that the get_user_pages() reference needs to be dropped when pfn_to_online_page() fails.
When soft_offline_page() is handed a pfn_valid() && !pfn_to_online_page() pfn the kernel hangs at dax-device shutdown due to a leaked reference.
Fixes: feec24a6139d ("mm, soft-offline: convert parameter to pfn") Cc: Andrew Morton akpm@linux-foundation.org Cc: Naoya Horiguchi nao.horiguchi@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Michal Hocko mhocko@kernel.org Cc: Oscar Salvador osalvador@suse.de Cc: stable@vger.kernel.org Signed-off-by: Dan Williams dan.j.williams@intel.com
mm/memory-failure.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 5a38e9eade94..78b173c7190c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1885,6 +1885,12 @@ static int soft_offline_free_page(struct page *page) return rc; } +static void put_ref_page(struct page *page) +{
- if (page)
put_page(page);+}
/**
- soft_offline_page - Soft offline a page.
- @pfn: pfn to soft-offline
@@ -1910,20 +1916,26 @@ static int soft_offline_free_page(struct page *page) int soft_offline_page(unsigned long pfn, int flags) { int ret;
- struct page *page; bool try_again = true;
- struct page *page, *ref_page = NULL;
- WARN_ON_ONCE(!pfn_valid(pfn) && (flags & MF_COUNT_INCREASED));
if (!pfn_valid(pfn)) return -ENXIO;
- if (flags & MF_COUNT_INCREASED)
ref_page = pfn_to_page(pfn);- /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ page = pfn_to_online_page(pfn);
- if (!page)
- if (!page) {
put_ref_page(ref_page);- }
if (PageHWPoison(page)) { pr_info("%s: %#lx page already poisoned\n", __func__, pfn);
if (flags & MF_COUNT_INCREASED)put_page(page);
put_ref_page(ref_page);
Reviewed-by: David Hildenbrand david@redhat.com