From c2afd98c87c21d593d892b99df2e17b9523455cb Mon Sep 17 00:00:00 2001 From: Kamal Agrawal Date: Mon, 13 Feb 2023 16:51:37 +0530 Subject: [PATCH] msm: kgsl: Make sure that pool pages don't have any extra references Before putting a page back in the pool be sure that it doesn't have any additional references that would be a signal that somebody else is looking at the page and that it would be a bad idea to keep it around and run the risk of accidentally handing it to a different process. Change-Id: Ic0dedbad0cf2ffb34b76ad23e393c5a911114b82 Signed-off-by: Jordan Crouse Signed-off-by: Kamal Agrawal --- drivers/gpu/msm/kgsl_pool.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/msm/kgsl_pool.c b/drivers/gpu/msm/kgsl_pool.c index cd5f8e3efe98..77bb50ded36f 100644 --- a/drivers/gpu/msm/kgsl_pool.c +++ b/drivers/gpu/msm/kgsl_pool.c @@ -1,4 +1,5 @@ /* Copyright (c) 2016-2017, The Linux Foundation. All rights reserved. + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and @@ -83,6 +84,15 @@ _kgsl_pool_zero_page(struct page *p, unsigned int pool_order) static void _kgsl_pool_add_page(struct kgsl_page_pool *pool, struct page *p) { + /* + * Sanity check to make sure we don't re-pool a page that + * somebody else has a reference to. + */ + if (WARN_ON_ONCE(unlikely(page_count(p) > 1))) { + __free_pages(p, pool->pool_order); + return; + } + _kgsl_pool_zero_page(p, pool->pool_order); spin_lock(&pool->list_lock);