+ mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch added to -mm tree

+ mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid]
has been added to the -mm tree.  Its filename is
     mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
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/20210902121242.41607-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/mm/page_alloc.c~mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact
+++ a/mm/page_alloc.c
@@ -5604,8 +5604,8 @@ 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);
@@ -5629,8 +5629,8 @@ 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)
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-page_allocc-remove-meaningless-vm_bug_on-in-pindex_to_order.patch
mm-page_allocc-simplify-the-code-by-using-macro-k.patch
mm-page_allocc-fix-obsolete-comment-in-free_pcppages_bulk.patch
mm-page_allocc-use-helper-function-zone_spans_pfn.patch
mm-page_allocc-avoid-allocating-highmem-pages-via-alloc_pages_exact.patch
mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate.patch
mm-page_isolation-guard-against-possible-putback-unisolated-page.patch
mm-memory_hotplug-make-hwpoisoned-dirty-swapcache-pages-unmovable.patch
mm-zsmallocc-close-race-window-between-zs_pool_dec_isolated-and-zs_unregister_migration.patch
mm-zsmallocc-combine-two-atomic-ops-in-zs_pool_dec_isolated.patch