From 628622904b8d229591134e44efd6608a7541eb89 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 14 May 2021 17:27:22 -0700 Subject: [PATCH] ksm: revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()" 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. Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2105092253500.1127@eggly.anvils Signed-off-by: Hugh Dickins Cc: Miaohe Lin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/ksm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/ksm.c b/mm/ksm.c index 6bbe314..2f3aaeb 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -776,11 +776,12 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) 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)) -- 2.7.4