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 A6D27C433EF for ; Tue, 9 Nov 2021 01:29:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FE2A610CB for ; Tue, 9 Nov 2021 01:29:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243366AbhKIBcP (ORCPT ); Mon, 8 Nov 2021 20:32:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:58546 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243075AbhKIB07 (ORCPT ); Mon, 8 Nov 2021 20:26:59 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D729761406; Tue, 9 Nov 2021 01:10:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636420210; bh=YU2DXVZ+7h37o9JM5RlfJzMMJWMvl2Iw7jDeJIdyAxc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ifEafSvxUL2kJtIv2QDmxyPWW4d62XootW5yta7w+kyX3mRvm47AEJMxDSsZtQy0M leFfQN1R+9Hs/OZkX75QHzc8V1Oe+2tkLPRdWhCfrgEQzbcAIfk1pQMMPNs1moJ7C2 GgxDdHsNVORJu32lSFIqXyqSMKG+NnndUa+GrWE+AGj+nb+Yc0w1KwkAgdmrns1kdB ZJ6N60AuWH9ymvCJrtYOZXwolpDJ76G3/9V/gB/X0yIY2wKmbBY+J4eD6UvBnMb5LL S8CrnJSUwcyBz1TyxVh5g/il505NSkSrnNS7BeE81WuOTVyn4FEOK3YQM26HQu4WNE TxrZWrmIt92LQ== 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 4.4 27/30] ARM: clang: Do not rely on lr register for stacktrace Date: Mon, 8 Nov 2021 20:09:15 -0500 Message-Id: <20211109010918.1192063-27-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109010918.1192063-1-sashal@kernel.org> References: <20211109010918.1192063-1-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