From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] ksm: Revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()"
Date: Sun, 9 May 2021 22:59:34 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.11.2105092253500.1127@eggly.anvils> (raw)
This reverts commit 3e96b6a2e9ad929a3230a22f4d64a74671a0720b.
General Protection Fault in rmap_walk_ksm() under memory pressure:
remove_rmap_item_from_tree() needs to take page lock, of course.
Signed-off-by: Hugh Dickins <hughd@google.com>
---
mm/ksm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 5.13-rc1/mm/ksm.c 2021-05-09 17:03:44.010422188 -0700
+++ linux/mm/ksm.c 2021-05-09 22:12:39.403008350 -0700
@@ -776,11 +776,12 @@ static void remove_rmap_item_from_tree(s
struct page *page;
stable_node = rmap_item->head;
- page = get_ksm_page(stable_node, GET_KSM_PAGE_NOLOCK);
+ page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);
if (!page)
goto out;
hlist_del(&rmap_item->hlist);
+ unlock_page(page);
put_page(page);
if (!hlist_empty(&stable_node->hlist))
next reply other threads:[~2021-05-10 6:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-10 5:59 Hugh Dickins [this message]
2021-05-10 6:57 ` [PATCH] ksm: Revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()" Miaohe Lin
2021-05-10 23:42 ` Hugh Dickins
2021-05-11 1:40 ` Miaohe Lin
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