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 83656C433EF for ; Tue, 9 Nov 2021 01:26:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6364E610A3 for ; Tue, 9 Nov 2021 01:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243834AbhKIB2c (ORCPT ); Mon, 8 Nov 2021 20:28:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:50242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243506AbhKIBXW (ORCPT ); Mon, 8 Nov 2021 20:23:22 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8F77C61A65; Tue, 9 Nov 2021 01:09:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636420146; bh=YU2DXVZ+7h37o9JM5RlfJzMMJWMvl2Iw7jDeJIdyAxc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZFK2vAYGwyo7ouQhiN9j8Al+WO2xlzOLBlazdC0ag9om7D5BIb1VAN2CXDtRGS1b2 MJKhB399Oc45cgNwqdu2wtAC6IcOkJLV9QyqtlDovxEUGULNPJiDLQTUVMaUrm95W2 ZYtmwgh/AlWOWxjoo91yU72gk+KGjU9YyqQqSCy4ga4UuXcA87S6yXDGpuoigdwu8J gAVqYCVhRoY57cYfnP3XjYs7P5QmIJkNS9CmF5s8H1fWOqROcGy94AC6/upQn8oL49 Qzudmfmtv0re7m77lHoNA2ckvCaVPbUNGCZ7FH8JWyEY9bZYMBtsgMRWaEpmxqVNcS WJOAqk1+chY/g== 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 4.9 29/33] ARM: clang: Do not rely on lr register for stacktrace Date: Mon, 8 Nov 2021 20:08:03 -0500 Message-Id: <20211109010807.1191567-29-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109010807.1191567-1-sashal@kernel.org> References: <20211109010807.1191567-1-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 6e8a50de40e2b..c10c1de244eba 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -51,8 +51,7 @@ 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