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mm: fix page reference leak in soft_offline_page()

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The conversion to move pfn_to_online_page() internal to
soft_offline_page() missed that the get_user_pages() reference taken by
the madvise() path needs to be dropped when pfn_to_online_page() fails.

Note the direct sysfs-path to soft_offline_page() does not perform a
get_user_pages() lookup.

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.

Link: https://lkml.kernel.org/r/161058501210.1840162.8108917599181157327.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: feec24a613 ("mm, soft-offline: convert parameter to pfn")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams 2021-01-23 21:01:52 -08:00 committed by Linus Torvalds
parent 251b5497c5
commit dad4e5b390
1 changed files with 16 additions and 4 deletions
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20
mm/memory-failure.c
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@ -1885,6 +1885,12 @@ static int soft_offline_free_page(struct page *page)
return rc; return rc;
} }
static void put_ref_page(struct page *page)
{
if (page)
put_page(page);
}
/** /**
* soft_offline_page - Soft offline a page. * soft_offline_page - Soft offline a page.
* @pfn: pfn to soft-offline * @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 soft_offline_page(unsigned long pfn, int flags)
{ {
int ret; int ret;
struct page *page;
bool try_again = true; bool try_again = true;
struct page *page, *ref_page = NULL;
WARN_ON_ONCE(!pfn_valid(pfn) && (flags & MF_COUNT_INCREASED));
if (!pfn_valid(pfn)) if (!pfn_valid(pfn))
return -ENXIO; return -ENXIO;
if (flags & MF_COUNT_INCREASED)
ref_page = pfn_to_page(pfn);
/* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
page = pfn_to_online_page(pfn); page = pfn_to_online_page(pfn);
if (!page) if (!page) {
put_ref_page(ref_page);
return -EIO; return -EIO;
}
if (PageHWPoison(page)) { if (PageHWPoison(page)) {
pr_info("%s: %#lx page already poisoned\n", __func__, pfn); pr_info("%s: %#lx page already poisoned\n", __func__, pfn);
if (flags & MF_COUNT_INCREASED) put_ref_page(ref_page);
put_page(page);
return 0; return 0;
} }