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From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <vbabka@suse.cz>, <sfr@canb.auug.org.au>, <peterz@infradead.org>,
	<mgorman@techsingularity.net>, <david@redhat.com>,
	<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
	<linmiaohe@huawei.com>
Subject: [PATCH v2 5/5] mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid]
Date: Thu, 2 Sep 2021 20:12:42 +0800	[thread overview]
Message-ID: <20210902121242.41607-6-linmiaohe@huawei.com> (raw)
In-Reply-To: <20210902121242.41607-1-linmiaohe@huawei.com>

Don't use with __GFP_HIGHMEM because page_address() cannot represent
highmem pages without kmap(). Newly allocated pages would leak as
page_address() will return NULL for highmem pages here. But It works
now because the callers do not specify __GFP_HIGHMEM now.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/page_alloc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9c09dcb24149..e1d0e27d005a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5614,8 +5614,8 @@ void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
 	unsigned int order = get_order(size);
 	unsigned long addr;
 
-	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
-		gfp_mask &= ~__GFP_COMP;
+	if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
+		gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
 
 	addr = __get_free_pages(gfp_mask, order);
 	return make_alloc_exact(addr, order, size);
@@ -5639,8 +5639,8 @@ void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
 	unsigned int order = get_order(size);
 	struct page *p;
 
-	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
-		gfp_mask &= ~__GFP_COMP;
+	if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
+		gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
 
 	p = alloc_pages_node(nid, gfp_mask, order);
 	if (!p)
-- 
2.23.0


  parent reply	other threads:[~2021-09-02 12:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 12:12 [PATCH v2 0/5] Cleanups and fixup for page_alloc Miaohe Lin
2021-09-02 12:12 ` [PATCH v2 1/5] mm/page_alloc.c: remove meaningless VM_BUG_ON() in pindex_to_order() Miaohe Lin
2021-09-02 12:12 ` [PATCH v2 2/5] mm/page_alloc.c: simplify the code by using macro K() Miaohe Lin
2021-09-02 12:12 ` [PATCH v2 3/5] mm/page_alloc.c: fix obsolete comment in free_pcppages_bulk() Miaohe Lin
2021-09-02 14:03   ` Mel Gorman
2021-09-02 12:12 ` [PATCH v2 4/5] mm/page_alloc.c: use helper function zone_spans_pfn() Miaohe Lin
2021-09-02 12:12 ` Miaohe Lin [this message]
2021-09-02 12:16   ` [PATCH v2 5/5] mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid] David Hildenbrand
2021-09-02 12:45     ` Miaohe Lin

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