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[195.135.221.5]) by mx.google.com with ESMTPS id b6si809766edi.277.2019.02.08.01.06.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 01:06:23 -0800 (PST) Received-SPF: pass (google.com: domain of osalvador@suse.de designates 195.135.221.5 as permitted sender) client-ip=195.135.221.5; Authentication-Results: mx.google.com; spf=pass (google.com: domain of osalvador@suse.de designates 195.135.221.5 as permitted sender) smtp.mailfrom=osalvador@suse.de Received: from emea4-mta.ukb.novell.com ([10.120.13.87]) by smtp.nue.novell.com with ESMTP (TLS encrypted); Fri, 08 Feb 2019 10:06:22 +0100 Received: from d104.suse.de (nwb-a10-snat.microfocus.com [10.120.13.202]) by emea4-mta.ukb.novell.com with ESMTP (NOT encrypted); Fri, 08 Feb 2019 09:06:14 +0000 From: Oscar Salvador To: akpm@linux-foundation.org Cc: mhocko@suse.com, david@redhat.com, anthony.yznaga@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oscar Salvador Subject: [PATCH] mm,memory_hotplug: Explicitly pass the head to isolate_huge_page Date: Fri, 8 Feb 2019 10:06:04 +0100 Message-Id: <20190208090604.975-1-osalvador@suse.de> X-Mailer: git-send-email 2.13.7 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: isolate_huge_page() expects we pass the head of hugetlb page to it: bool isolate_huge_page(...) { ... VM_BUG_ON_PAGE(!PageHead(page), page); ... } While I really cannot think of any situation where we end up with a non-head page between hands in do_migrate_range(), let us make sure the code is as sane as possible by explicitly passing the Head. Since we already got the pointer, it does not take us extra effort. Signed-off-by: Oscar Salvador --- mm/memory_hotplug.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 656ff386ac15..d5f7afda67db 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1378,12 +1378,12 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) if (PageHuge(page)) { struct page *head = compound_head(page); - pfn = page_to_pfn(head) + (1< PFN_SECTION_SHIFT) { ret = -EBUSY; break; } - isolate_huge_page(page, &source); + pfn = page_to_pfn(head) + (1<