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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F28FECAAD2 for ; Mon, 29 Aug 2022 11:15:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229656AbiH2LPM (ORCPT ); Mon, 29 Aug 2022 07:15:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231673AbiH2LO3 (ORCPT ); Mon, 29 Aug 2022 07:14:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8EA3D67446; Mon, 29 Aug 2022 04:10:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 35789611DA; Mon, 29 Aug 2022 11:10:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F423C433D6; Mon, 29 Aug 2022 11:10:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661771415; bh=/YP6VvDcJ9DScd+mjxxX5q2txVxjWzz7n9jvS0JRzxc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yQsWaH4rwG2JkJU5h1VUCIkGbaaSkZDmwkuLJl/80qy5YndP87l/2nEkhW6XOjEAo FFIwcbpXY9vIpBmpQyvzgR8AMdyKXuWKP0rIR0+26L4sTD30yhx1q0YJyvYEoU+0ly b7Q5nFwf07UVJ0PWKniKV/G+B53H78ILlFt8en+U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Zhongjin , Ingo Molnar , "Steven Rostedt (Google)" Subject: [PATCH 5.15 101/136] x86/unwind/orc: Unwind ftrace trampolines with correct ORC entry Date: Mon, 29 Aug 2022 12:59:28 +0200 Message-Id: <20220829105808.840578337@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220829105804.609007228@linuxfoundation.org> References: <20220829105804.609007228@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chen Zhongjin commit fc2e426b1161761561624ebd43ce8c8d2fa058da upstream. When meeting ftrace trampolines in ORC unwinding, unwinder uses address of ftrace_{regs_}call address to find the ORC entry, which gets next frame at sp+176. If there is an IRQ hitting at sub $0xa8,%rsp, the next frame should be sp+8 instead of 176. It makes unwinder skip correct frame and throw warnings such as "wrong direction" or "can't access registers", etc, depending on the content of the incorrect frame address. By adding the base address ftrace_{regs_}caller with the offset *ip - ops->trampoline*, we can get the correct address to find the ORC entry. Also change "caller" to "tramp_addr" to make variable name conform to its content. [ mingo: Clarified the changelog a bit. ] Fixes: 6be7fa3c74d1 ("ftrace, orc, x86: Handle ftrace dynamically allocated trampolines") Signed-off-by: Chen Zhongjin Signed-off-by: Ingo Molnar Reviewed-by: Steven Rostedt (Google) Cc: Link: https://lore.kernel.org/r/20220819084334.244016-1-chenzhongjin@huawei.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/unwind_orc.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -93,22 +93,27 @@ static struct orc_entry *orc_find(unsign static struct orc_entry *orc_ftrace_find(unsigned long ip) { struct ftrace_ops *ops; - unsigned long caller; + unsigned long tramp_addr, offset; ops = ftrace_ops_trampoline(ip); if (!ops) return NULL; + /* Set tramp_addr to the start of the code copied by the trampoline */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) - caller = (unsigned long)ftrace_regs_call; + tramp_addr = (unsigned long)ftrace_regs_caller; else - caller = (unsigned long)ftrace_call; + tramp_addr = (unsigned long)ftrace_caller; + + /* Now place tramp_addr to the location within the trampoline ip is at */ + offset = ip - ops->trampoline; + tramp_addr += offset; /* Prevent unlikely recursion */ - if (ip == caller) + if (ip == tramp_addr) return NULL; - return orc_find(caller); + return orc_find(tramp_addr); } #else static struct orc_entry *orc_ftrace_find(unsigned long ip)