Commit fd476720 authored Oct 15, 2020 by Naoya Horiguchi Committed by Linus Torvalds Oct 16, 2020

mm,hwpoison-inject: don't pin for hwpoison_filter



Another memory error injection interface debugfs:hwpoison/corrupt-pfn also
takes bogus refcount for hwpoison_filter().  It's justified because this
does a coarse filter, expecting that memory_failure() redoes the check for
sure.

Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-4-osalvador@suse.de


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 1b473bec

mm/hwpoison-inject.c

+5 −13

Original line number	Diff line number	Diff line
		@@ -26,11 +26,6 @@ static int hwpoison_inject(void *data, u64 val)

		p = pfn_to_page(pfn);
		hpage = compound_head(p);
		/*
		* This implies unable to support free buddy pages.
		*/
		if (!get_hwpoison_page(p))
		return 0;

		if (!hwpoison_filter_enable)
		goto inject;
		@@ -40,23 +35,20 @@ static int hwpoison_inject(void *data, u64 val)
		* This implies unable to support non-LRU pages.
		*/
		if (!PageLRU(hpage) && !PageHuge(p))
		goto put_out;
		return 0;

		/*
		* do a racy check with elevated page count, to make sure PG_hwpoison
		* will only be set for the targeted owner (or on a free page).
		* do a racy check to make sure PG_hwpoison will only be set for
		* the targeted owner (or on a free page).
		* memory_failure() will redo the check reliably inside page lock.
		*/
		err = hwpoison_filter(hpage);
		if (err)
		goto put_out;
		return 0;

		inject:
		pr_info("Injecting memory failure at pfn %#lx\n", pfn);
		return memory_failure(pfn, MF_COUNT_INCREASED);
		put_out:
		put_hwpoison_page(p);
		return 0;
		return memory_failure(pfn, 0);
		}

		static int hwpoison_unpoison(void *data, u64 val)