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[198.145.29.99]) by mx.google.com with ESMTPS id l13si144250pjq.69.2019.06.06.14.46.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 06 Jun 2019 14:46:44 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=dfZnA3Lo; spf=pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 309C320673; Thu, 6 Jun 2019 21:46:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559857604; bh=e8zSxF2YstjZdXDoPM2QroSTxqWSMLpjdXaDzNM/bHM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=dfZnA3LoZI3kcekTvMdg7vm4wyUFToyxp29Scm6Cs7omCJytnHlzwlMXFqlGds2ht tKZ/OehCLO9EzgtHqjvJGedCRwMgeIGQKU+kGulTg4LF9TrwyYbFy3R+yo1Vi1wg+x L5CEq0PQe3DdZ/43QWfXSG4GV8UOuKXGuJHoNWd0= Date: Thu, 6 Jun 2019 14:46:43 -0700 From: Andrew Morton To: Dan Williams Cc: stable@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, osalvador@suse.de, mhocko@suse.com Subject: Re: [PATCH v9 11/12] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields Message-Id: <20190606144643.4f3363db9499ebbf8f76e62e@linux-foundation.org> In-Reply-To: <155977193862.2443951.10284714500308539570.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> <155977193862.2443951.10284714500308539570.stgit@dwillia2-desk3.amr.corp.intel.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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 Wed, 05 Jun 2019 14:58:58 -0700 Dan Williams wrote: > At namespace creation time there is the potential for the "expected to > be zero" fields of a 'pfn' info-block to be filled with indeterminate > data. While the kernel buffer is zeroed on allocation it is immediately > overwritten by nd_pfn_validate() filling it with the current contents of > the on-media info-block location. For fields like, 'flags' and the > 'padding' it potentially means that future implementations can not rely > on those fields being zero. > > In preparation to stop using the 'start_pad' and 'end_trunc' fields for > section alignment, arrange for fields that are not explicitly > initialized to be guaranteed zero. Bump the minor version to indicate it > is safe to assume the 'padding' and 'flags' are zero. Otherwise, this > corruption is expected to benign since all other critical fields are > explicitly initialized. > > Fixes: 32ab0a3f5170 ("libnvdimm, pmem: 'struct page' for pmem") > Cc: > Signed-off-by: Dan Williams The cc:stable in [11/12] seems odd. Is this independent of the other patches? If so, shouldn't it be a standalone thing which can be prioritized?