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 D26CBC43217 for ; Tue, 9 Nov 2021 01:22:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C151D610E9 for ; Tue, 9 Nov 2021 01:22:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243133AbhKIBXM (ORCPT ); Mon, 8 Nov 2021 20:23:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:47860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243158AbhKIBTc (ORCPT ); Mon, 8 Nov 2021 20:19:32 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0DB1561284; Tue, 9 Nov 2021 01:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636420073; bh=fZXrAMowt1mPhO6b8vKZbcOJ66dxfQP3LqK1emOm2MI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eFFF5u50Swqb8NtLkN64ubK5qlNUCu5iXIce0ecHF6kUha/yDuzpiSfrtnrWoIBCj YYT8g4ZslL1ZNlThlf03e/YEndnBNx4ZHQ7babSe/Wux7ujd2A9HN5kQGJfSoxU55J EhdJoBYzEauX8r4LAnDLBrSzAlqx4P5LMP3FVyS77nAeP5kkWJ2nbEMVyLTXKaI7MY BXSgFtMHeb7v8U6T5N06rXk7darWiBuuVSblxg0018L5ifiNfZvYpXy+8QL6PZKL1d 04LAcTpCM2g9v3bGtLpu1kMZucwukCYpi9MpKKejpjiQty0hIcZ1S1QJ799Og49W1L pBCuNiU6G0sbw== 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 4.14 33/39] ARM: clang: Do not rely on lr register for stacktrace Date: Mon, 8 Nov 2021 20:06:43 -0500 Message-Id: <20211109010649.1191041-33-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109010649.1191041-1-sashal@kernel.org> References: <20211109010649.1191041-1-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 ba9b9a77bcd2c..31af81d46aaed 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -52,8 +52,7 @@ 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