Messages in this thread | | | Subject | Re: [PATCH v2 5/5] mm/page_alloc.c: avoid allocating highmem pages via alloc_pages_exact[_nid] | From | David Hildenbrand <> | Date | Thu, 2 Sep 2021 14:16:16 +0200 |
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On 02.09.21 14:12, Miaohe Lin wrote: > 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) >
Ideally we would convert this WARN_ON_ONCE() to pr_warn_once(), but I guess this really never ever happens on a production system and would get caught early while testing.
Reviewed-by: David Hildenbrand <david@redhat.com>
-- Thanks,
David / dhildenb
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