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authorHugh Dickins <hughd@google.com>2021-05-14 17:27:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-14 19:41:32 -0700
commit628622904b8d229591134e44efd6608a7541eb89 (patch)
tree94a2315b50117f96e1f732ed698df1b6f70a1ea1
parent7ed9d238c7dbb1fdb63ad96a6184985151b0171c (diff)
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 <hughd@google.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/ksm.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 6bbe314c5260..2f3aaeb34a42 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))