[107/262] mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid]

Commit Message

Andrew Morton Nov. 5, 2021, 8:40 p.m. UTC

From: Miaohe Lin <[e-mail]>
Subject: mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid]

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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Miaohe Lin <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephen Rothwell <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

--- a/mm/page_alloc.c~mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact
+++ a/mm/page_alloc.c
@@ -5610,8 +5610,8 @@  void *alloc_pages_exact(size_t size, gfp
 	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);
@@ -5635,8 +5635,8 @@  void * __meminit alloc_pages_exact_nid(i
 	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)