From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9EADC71159 for ; Fri, 18 Aug 2023 17:10:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243670AbjHRRJj (ORCPT ); Fri, 18 Aug 2023 13:09:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378911AbjHRRJe (ORCPT ); Fri, 18 Aug 2023 13:09:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28C403C2D; Fri, 18 Aug 2023 10:09:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BB91A62BD3; Fri, 18 Aug 2023 17:09:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4F27C433C8; Fri, 18 Aug 2023 17:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692378571; bh=go70K6iNIJWJf0elUmAhaiRiRebNiH0/0hUJeSfZDc8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hyC/8Qxibepj0bkrW5M0UTLFWLcMlbMpYWY3qzspmwZNYlOo7NZbnWF9Yup5G452U mg8spiw62TQr4TEMsG3Kx6WrgRcuMv7JjZ+XxZNk+xfeboahIV9y51KO5MbX17eF09 tvemSlkF/GstlHBkIViv9PolCjtqfPHnbHTK7RFexD21lfk41LgRnJ52Xon5uf+rie 2a+7DNY1C2Fd7kKlqDfDXcP8X4AOjPHM42G61kD+W/IfsHtsOYjVWpzE7DMjX77wby AkO7ZVMsXRKTm5ff0Ox+ijIisjAjKamyq7oCiylpucb6L12XKL6dL8q75LQRbQ2WaM F4uKQT9//WtVw== Received: (nullmailer pid 212309 invoked by uid 1000); Fri, 18 Aug 2023 17:09:29 -0000 Date: Fri, 18 Aug 2023 12:09:29 -0500 From: Rob Herring To: Rik van Riel Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, Frank Rowand , devicetree@vger.kernel.org Subject: Re: [PATCH] mm,ima,kexec,of: use memblock_free_late from ima_free_kexec_buffer Message-ID: <20230818170929.GA151785-robh@kernel.org> References: <20230817135759.0888e5ef@imladris.surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230817135759.0888e5ef@imladris.surriel.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Aug 17, 2023 at 01:57:59PM -0400, Rik van Riel wrote: > The code calling ima_free_kexec_buffer runs long after the memblock > allocator has already been torn down, potentially resulting in a use > after free in memblock_isolate_range. > > With KASAN or KFENCE, this use after free will result in a BUG > from the idle task, and a subsequent kernel panic. > > Switch ima_free_kexec_buffer over to memblock_free_late to avoid > that issue. > > Fixes: fee3ff99bc67 ("powerpc: Move arch independent ima kexec functions to > drivers/of/kexec.c") Didn't powerpc have the same issue before this commit? The move changed memblock_free() to memblock_phys_free(), but otherwise the code was the same. But wait, the old code looks broken as it reads a phys addr from DT and passes that to memblock_free() which wants a virt addr. Probably should have fixed that before moving things. I guess the Fixes here is right and powerpc needs a different backport for before commit fee3ff99bc67 if they care. > Cc: stable@kernel.org > Signed-off-by: Rik van Riel > Suggested-by: Mike Rappoport > --- > drivers/of/kexec.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c > index f26d2ba8a371..68278340cecf 100644 > --- a/drivers/of/kexec.c > +++ b/drivers/of/kexec.c > @@ -184,7 +184,8 @@ int __init ima_free_kexec_buffer(void) > if (ret) > return ret; > > - return memblock_phys_free(addr, size); > + memblock_free_late(addr, size); > + return 0; > } > #endif > > -- > 2.41.0 >