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 9786EC433F5 for ; Wed, 24 Nov 2021 13:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345949AbhKXNEw (ORCPT ); Wed, 24 Nov 2021 08:04:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:39968 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347784AbhKXNDS (ORCPT ); Wed, 24 Nov 2021 08:03:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 153A2619F9; Wed, 24 Nov 2021 12:36:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637757370; bh=n1IioQQzOH0POz7eaWR7ENdja0fn4A3UEsNKmpHT5UQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xJBfPTkQP5ya7OiXu7dJdQuHKglRqE/qc2nQbqJa6xVR4tGXkNAzN2OP6lc/VJ5Bn bCPbOhH9Hyc2tW7qNlAfE7Q4jcAy6lmrdckual3N1U4p+gnWNUWiIPvsjyd9kx+Esd H90pbEov8ypkKH6EwS577SF5amUnSLiuFzWUe3Wg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , Nick Desaulniers , "Steven Rostedt (VMware)" , Sasha Levin Subject: [PATCH 4.19 118/323] ARM: clang: Do not rely on lr register for stacktrace Date: Wed, 24 Nov 2021 12:55:08 +0100 Message-Id: <20211124115722.931188595@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115718.822024889@linuxfoundation.org> References: <20211124115718.822024889@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu [ Upstream commit b3ea5d56f212ad81328c82454829a736197ebccc ] Currently the stacktrace on clang compiled arm kernel uses the 'lr' register to find the first frame address from pt_regs. However, that is wrong after calling another function, because the 'lr' register is used by 'bl' instruction and never be recovered. As same as gcc arm kernel, directly use the frame pointer (r11) of the pt_regs to find the first frame address. Note that this fixes kretprobe stacktrace issue only with CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM, we need another fix. Signed-off-by: Masami Hiramatsu Reviewed-by: Nick Desaulniers Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin --- arch/arm/kernel/stacktrace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index d23ab9ec130a3..a452b859f485f 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -53,8 +53,7 @@ int notrace unwind_frame(struct stackframe *frame) frame->sp = frame->fp; frame->fp = *(unsigned long *)(fp); - frame->pc = frame->lr; - frame->lr = *(unsigned long *)(fp + 4); + frame->pc = *(unsigned long *)(fp + 4); #else /* check current frame pointer is within bounds */ if (fp < low + 12 || fp > high - 4) -- 2.33.0