From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DF554B486F for ; Mon, 28 Sep 2026 11:53:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790596403; cv=none; b=hCukn0TVZjFKNW099kAxogOGhAS6a9YzKvA2ehYlfDKKjsYorpbAIKmk3KPFH7N5jNIZFQknp/kHw5dxDsA2t7ziSVwQBXRosEKBEIvolJOo8g6JF6uIun6DSlL60Bry+gXl7AOXUvQCEgzc/GcV0RqI3yOSpYWUgOE0gEfIjyo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790596403; c=relaxed/simple; bh=6le2qXwVJmZxFOEVvq71j+C3kMrvOnmtqemgrLQwVYo=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=MG5yLiZt3sQbflFgWs8rrt/oDZ1AyAiSsc6N4tsJdRoLVV5a1MunD7OxWsIKW1BHwJO1/I5ewr/bjRlM+I/HlF0sWL1whq4VTZW4Xz9E4adyi9qRoIZ2UsGyl46ooktx8D2h9nQd5SScmhouVrc2xIHEcbfoojprV/xsMKYzpBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W0TynG5Z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="W0TynG5Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F12041F00893; Mon, 28 Sep 2026 11:53:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790596402; bh=6le2qXwVJmZxFOEVvq71j+C3kMrvOnmtqemgrLQwVYo=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=W0TynG5Zb+qBmxHk4Ve8GE1P2XCyN0Fm6pC6DglM70SivzXMt1GyHXVPz1G36hHAs 6EGO+TkxjURV56LVdaYgc+RBV+QOt0QYIL7hDFQwuq8ZaaCeHwQyXjvF4vk4Y0w2rf mhmV+4lMJAqLcMeLd3RrVYykFJe7a4BEfjZhBUgtBOXwFafhwucdKR6y7rT1khEb2Q ghWOrxqe1xhc57fXwDjL5snmF65B2QRH3D0yZtx9uFkkjyrb76/cix3oblPKfAitHg BL6WlVwLd98TFWGQTvoBRrSxRUp5XEgZyVIWMZsFG43H8cECuuyHYoGJTB5Mpa2T73 qqiuVBt7dxlCA== From: sashiko-bot@kernel.org Subject: Re: [PATCH net] s390/ism: Zerorize dmb at allocation Reply-To: sashiko-reviews@lists.linux.dev To: "Alexandra Winter" Cc: "Alexander Gordeev" , linux-s390@vger.kernel.org, "Heiko Carstens" , "Christian Borntraeger" , "Vasily Gorbik" In-Reply-To: <20260928114741.4135978-1-wintera@linux.ibm.com> References: <20260928114741.4135978-1-wintera@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 28 Sep 2026 11:53:21 +0000 Message-Id: <20260928115321.F12041F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Sashiko reported [1] that 'Missing __GFP_ZERO in folio_alloc() causes > uninitialized kernel memory to be exposed in the receive message buffer'. > An ism dmb is receive-only, so the data is not leaked to a remote peer. In > general the smc kernel module (dibs client) will only push newly received > data to userspace. We still should not have uninitialized data in a recei= ve > buffer. >=20 > Since > commit 750afb08ca71 ("cross-tree: phase out dma_zalloc_coherent()") > dma_alloc_coherent no longer required the __GFP_ZERO flag, but when > commit 83781384a96b ("s390/ism: Properly fix receive message buffer alloc= ation") > switched to folio_alloc(), it should have added back the __GFP_ZERO flag. >=20 > Add __GFP_ZERO flag and state in dibs.h that register_dbm() provides > a zerorized buffer (dibs_lo already does). >=20 > Link: https://lore.kernel.org/linux-s390/20260903143746.A5CC41F00A3A@smtp= .kernel.org/ [1] > Fixes: 83781384a96b ("s390/ism: Properly fix receive message buffer alloc= ation") > Signed-off-by: Alexandra Winter Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260928114741.4135= 978-1-wintera@linux.ibm.com?part=3D1