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 23358C433F5 for ; Mon, 15 Nov 2021 22:42:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C64963211 for ; Mon, 15 Nov 2021 22:42:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351411AbhKOWoM (ORCPT ); Mon, 15 Nov 2021 17:44:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:47396 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242360AbhKOSks (ORCPT ); Mon, 15 Nov 2021 13:40:48 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1A7AC6328C; Mon, 15 Nov 2021 18:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636999467; bh=LYR2W95ebjp7DRuQ9X3HmqQlJt75WLxMhBbupiA0wIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y9022DJJG64z25FRwhVDeCIOLmSlvbpIjqbakwir5lJW3KUlgBvGndSpLB+wS4Get 28ji65Rw2Y3G4IuzLDX0vKN58Y26C3oMwD76bJDNi6XlfVOHiLegaecGMu8Rt4aWQL u4dVGaLIxjBkQZgsRVZPwaZS5dB/xwJpr1yNTJ4M= 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 5.14 307/849] ARM: clang: Do not rely on lr register for stacktrace Date: Mon, 15 Nov 2021 17:56:30 +0100 Message-Id: <20211115165430.631643115@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165419.961798833@linuxfoundation.org> References: <20211115165419.961798833@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 76ea4178a55cb..db798eac74315 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -54,8 +54,7 @@ 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