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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0482C433EF for ; Tue, 9 Nov 2021 01:27:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 865A560FC2 for ; Tue, 9 Nov 2021 01:27:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243238AbhKIBaA (ORCPT ); Mon, 8 Nov 2021 20:30:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:44392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243281AbhKIBPY (ORCPT ); Mon, 8 Nov 2021 20:15:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id BEF6E61A0A; Tue, 9 Nov 2021 01:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636419987; bh=n1IioQQzOH0POz7eaWR7ENdja0fn4A3UEsNKmpHT5UQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q1joH7j/3x185sChkhoLgFowaIczOLA7StVThjAG9EZnwUz538nuR37wRcz6iEP0V apcT+HacTgF5FYNwepcTrO2EFzDMJOPZTb6ABDGMCZUu+UUBrwDPGU7clP0YqP5fzR 8cWVzeiTB/foJ2PhkfMHkJ/6N0dnXGy6RWABZbHCicGKLYJ53PAXyDTB9VkRQNOK/U Z5QCoYG+sUqjJ42bmendONmvRmCKPH/Oglsu+t4Co1fXFJ0Me2JR7ukIgpqQXinzLO 4afVmbOYu3ZT+XhjiU/GjAskYBkjjuA0N2DSBHvANuS39Vp/A0vTSf4zymkgGyXzqp BxvpfilsOMpQg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Masami Hiramatsu , Nick Desaulniers , Steven Rostedt , Sasha Levin , linux@armlinux.org.uk, nathan@kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 4.19 38/47] ARM: clang: Do not rely on lr register for stacktrace Date: Mon, 8 Nov 2021 12:50:22 -0500 Message-Id: <20211108175031.1190422-38-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211108175031.1190422-1-sashal@kernel.org> References: <20211108175031.1190422-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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