This patch is for stable branch linux-4.4-y.
On 2019/6/12 9:54, ZhangXiaoxu wrote:
The upstram commit 65d8fc777f6d ("futex: Remove requirement for lock_page() in get_futex_key()") use variable 'page' as the page head, when merge it to stable branch, the variable `page_head` is page head.
In the stable branch, the variable `page` not means the page head, when lock the page head, we should lock 'page_head', rather than 'page'.
It maybe lead a hung task problem.
Signed-off-by: ZhangXiaoxu zhangxiaoxu5@huawei.com Cc: stable@vger.kernel.org
kernel/futex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index ec9df5b..15d850f 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -593,8 +593,8 @@ again: * applies. If this is really a shmem page then the page lock * will prevent unexpected transitions. */
lock_page(page);shmem_swizzled = PageSwapCache(page) || page->mapping;
lock_page(page_head);shmem_swizzled = PageSwapCache(page_head) || page_head->mapping;