linux-kernel - [PATCH] mm: fix is_pinnable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Mon,  2 May 2022 10:35:58 -0700
From:   Minchan Kim <minchan@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
        John Hubbard <jhubbard@...dia.com>,
        John Dias <joaodias@...gle.com>,
        Minchan Kim <minchan@...nel.org>
Subject: [PATCH] mm: fix is_pinnable_page against on cma page

Pages on CMA area could have MIGRATE_ISOLATE as well as MIGRATE_CMA
so current is_pinnable_page could miss CMA pages which has MIGRATE_
ISOLATE. It ends up putting CMA pages longterm pinning possible on
pin_user_pages APIs so CMA allocation fails.

The CMA allocation path protects the migration type change race
using zone->lock but what GUP path need to know is just whether the
page is on CMA area or not rather than exact type. Thus, we don't
need zone->lock but just checks the migratype in either of
(MIGRATE_ISOLATE and MIGRATE_CMA).

Signed-off-by: Minchan Kim <minchan@...nel.org>
---
 include/linux/mm.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6acca5cecbc5..f59bbe3296e3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1625,8 +1625,10 @@ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma,
 #ifdef CONFIG_MIGRATION
 static inline bool is_pinnable_page(struct page *page)
 {
-	return !(is_zone_movable_page(page) || is_migrate_cma_page(page)) ||
-		is_zero_pfn(page_to_pfn(page));
+	int mt = get_pageblock_migratetype(page);
+
+	return !(is_zone_movable_page(page) || mt == MIGRATE_CMA ||
+		mt == MIGRATE_ISOLATE || is_zero_pfn(page_to_pfn(page)));
 }
 #else
 static inline bool is_pinnable_page(struct page *page)
-- 
2.36.0.464.gb9c8b46e94-goog