From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:50632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933163AbeD0OEQ (ORCPT ); Fri, 27 Apr 2018 10:04:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Burton , Rob Herring , Grant Likely , Frank Rowand , devicetree@vger.kernel.org, linux-mips@linux-mips.org, Ralf Baechle , Amit Pundir Subject: [PATCH 4.9 15/74] OF: Prevent unaligned access in of_alias_scan() Date: Fri, 27 Apr 2018 15:58:05 +0200 Message-Id: <20180427135710.534544535@linuxfoundation.org> In-Reply-To: <20180427135709.899303463@linuxfoundation.org> References: <20180427135709.899303463@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton commit de96ec2a77c6d06a423c2c495bb4a2f4299f3d9e upstream. When allocating a struct alias_prop, of_alias_scan() only requested that it be aligned on a 4 byte boundary. The struct contains pointers which leads to us attempting 64 bit writes on 64 bit systems, and if the CPU doesn't support unaligned memory accesses then this causes problems - for example on some MIPS64r2 CPUs including the "mips64r2-generic" QEMU emulated CPU it will trigger an address error exception. Fix this by requesting alignment for the struct alias_prop allocation matching that which the compiler expects, using the __alignof__ keyword. Signed-off-by: Paul Burton Acked-by: Rob Herring Reviewed-by: Grant Likely Cc: Frank Rowand Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14306/ Signed-off-by: Ralf Baechle Cc: Amit Pundir Signed-off-by: Greg Kroah-Hartman --- drivers/of/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -2109,7 +2109,7 @@ void of_alias_scan(void * (*dt_alloc)(u6 continue; /* Allocate an alias_prop with enough space for the stem */ - ap = dt_alloc(sizeof(*ap) + len + 1, 4); + ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap)); if (!ap) continue; memset(ap, 0, sizeof(*ap) + len + 1);