From patchwork Tue Mar 13 22:42:40 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: mm/page_alloc: fix boot hang in memmap_init_zone From: Daniel Vacek X-Patchwork-Id: 10281093 Message-Id: <20180313224240.25295-1-neelx@redhat.com> To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Sudeep Holla , Naresh Kamboju , Daniel Vacek , Andrew Morton , Mel Gorman , Michal Hocko , Paul Burton , Pavel Tatashin , Vlastimil Babka , stable@vger.kernel.org Date: Tue, 13 Mar 2018 23:42:40 +0100 On some architectures (reported on arm64) commit 864b75f9d6b01 ("mm/page_alloc: fix memmap_init_zone pageblock alignment") causes a boot hang. This patch fixes the hang making sure the alignment never steps back. Link: http://lkml.kernel.org/r/0485727b2e82da7efbce5f6ba42524b429d0391a.1520011945.git.neelx@redhat.com Fixes: 864b75f9d6b01 ("mm/page_alloc: fix memmap_init_zone pageblock alignment") Signed-off-by: Daniel Vacek Tested-by: Sudeep Holla Tested-by: Naresh Kamboju Cc: Andrew Morton Cc: Mel Gorman Cc: Michal Hocko Cc: Paul Burton Cc: Pavel Tatashin Cc: Vlastimil Babka Cc: --- mm/page_alloc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3d974cb2a1a1..e033a6895c6f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5364,9 +5364,14 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, * is not. move_freepages_block() can shift ahead of * the valid region but still depends on correct page * metadata. + * Also make sure we never step back. */ - pfn = (memblock_next_valid_pfn(pfn, end_pfn) & + unsigned long next_pfn; + + next_pfn = (memblock_next_valid_pfn(pfn, end_pfn) & ~(pageblock_nr_pages-1)) - 1; + if (next_pfn > pfn) + pfn = next_pfn; #endif continue; }