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[209.85.220.65]) by mx.google.com with SMTPS id x1sor4101008lff.8.2019.06.18.13.02.55 for (Google Transport Security); Tue, 18 Jun 2019 13:02:55 -0700 (PDT) Received-SPF: pass (google.com: domain of vdavydov.dev@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=D4LqXjau; spf=pass (google.com: domain of vdavydov.dev@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=vdavydov.dev@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=cVl3SIklS0nHd797FYY4cxHoZEAnPslNYDQOv5OhMDM=; b=D4LqXjauq6e8L92SXdCI8dBOeZ9g3qnR+MvRfoDQP4UPl32roBpvGWprF3TjlmHSja eZ/6/ZjWzgRN9htttHJTrPzVJCoFvbIqpDA3vC1Cl8utSLu6XzXuxp7AabXcEV/Om6He yHiGKcbb2hB4xqghyhAsPiwk4UDzPPVak57pe2KgOS495X1pgno1vQnCtMEqE80s7SDd b/xHq26uOBUeyQq+iykM4OWAPJ5VZU59856GZ2QUrHkBfHjmAmn1pe6xmy0ce97q8t4y IfDjJ3INQeQbB5asZ/xxIwCfBifBBZjV8Yfyh2WDBB5G9dWZfMSeieDwA07Xq9c2du8P K49g== X-Google-Smtp-Source: APXvYqzKO9zG2G36ym9WsDHSLpShB5YrpwSynDJM7DvNbZeZWMwp4g4634Uhi3PMXIvAfLocbMbxAg== X-Received: by 2002:a05:6512:29a:: with SMTP id j26mr26109062lfp.44.1560888175432; Tue, 18 Jun 2019 13:02:55 -0700 (PDT) Received: from esperanza ([176.120.239.149]) by smtp.gmail.com with ESMTPSA id j23sm1621386lfb.93.2019.06.18.13.02.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 18 Jun 2019 13:02:54 -0700 (PDT) Date: Tue, 18 Jun 2019 23:02:51 +0300 From: Vladimir Davydov To: Andrew Morton Cc: Colin King , Michal Hocko , Mike Rapoport , Mel Gorman , Stephen Rothwell , Andrey Ryabinin , linux-mm@kvack.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: idle-page: fix oops because end_pfn is larger than max_pfn Message-ID: <20190618200251.hd2uk6qzyvsy55py@esperanza> References: <20190618124352.28307-1-colin.king@canonical.com> <20190618124502.7b9c32a00a54f0c618a12ca4@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190618124502.7b9c32a00a54f0c618a12ca4@linux-foundation.org> 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: On Tue, Jun 18, 2019 at 12:45:02PM -0700, Andrew Morton wrote: > On Tue, 18 Jun 2019 13:43:52 +0100 Colin King wrote: > > > From: Colin Ian King > > > > Currently the calcuation of end_pfn can round up the pfn number to > > more than the actual maximum number of pfns, causing an Oops. Fix > > this by ensuring end_pfn is never more than max_pfn. > > > > This can be easily triggered when on systems where the end_pfn gets > > rounded up to more than max_pfn using the idle-page stress-ng > > stress test: > > > > cc Vladimir. This seems rather obvious - I'm wondering if the code was > that way for some subtle reason? No subtle reason at all - just a bug. The patch looks good to me, Acked-by: Vladimir Davydov