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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 75B6D40006 X-Rspamd-Server: rspam05 X-Stat-Signature: zuxpj15n4gdqeoup6nzo6crom4pnt1jm X-Rspam-User: X-HE-Tag: 1758610075-788169 X-HE-Meta: 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 St7gTRMX 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 23/09/25 5:49 am, Wei Yang wrote: > Commit 5e27a2df03b8 ("mm/page_alloc: add alloc_contig_pages()") > introduced generic method for alloc_contig_pages(). But the alignment > calculation seems wrong. > > Since ALIGN() only accept power of two value, while nr_pages could be > any positive one, the result is not defined. > > Use roundup() to calculate the correct alignment. > > Fixes: 5e27a2df03b8 ("mm/page_alloc: add alloc_contig_pages()") The ALIGN() statement was even before this, but not sure if a potential caller with non-power-of-2 nr_pages was present then. > Signed-off-by: Wei Yang > Cc: Anshuman Khandual > Cc: Oscar Salvador > Cc: Brendan Jackman > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Suren Baghdasaryan > Cc: Vlastimil Babka > Cc: Wei Yang > Cc: Zi Yan > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index a1bcc1e003c7..a17a6014e3db 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7095,7 +7095,7 @@ struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_mask, > gfp_zone(gfp_mask), nodemask) { > spin_lock_irqsave(&zone->lock, flags); > > - pfn = ALIGN(zone->zone_start_pfn, nr_pages); > + pfn = roundup(zone->zone_start_pfn, nr_pages); > while (zone_spans_last_pfn(zone, pfn, nr_pages)) { > if (pfn_range_valid_contig(pfn, nr_pages)) { > /* The kernel-doc above alloc_contig_pages_noprof reads: "If nr_pages is a power of two, then allocated range is always guaranteed to be aligned to same nr_pages." This means that the function gives no guarantee on alignment of non-power-of-2 requests - and why should it? It doesn't make any sense to align pfn to 7 if nr_pages is 7.