From patchwork Mon Sep 16 10:27:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleg Nesterov X-Patchwork-Id: 13805247 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4893C3ABA2 for ; Mon, 16 Sep 2024 10:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=yMOO+5zuP47cm2PSmBG0SvJ4q2L6HUZ6VPVcAFdwe5s=; b=Q8ZIfN1+1dAnetTgmlKmcA9cRH AOb+GKfs/OofxESnqC/fyiNaUwJKNhJqti9iBOcpMCwlKfakAhm4TruPE+9266noLCuEVjy7tkw6t pbNaospbrWXLpm85rbEKrprQZxUmLmbEowvTXh7HdkHZcUcZ1BIROFZBe7/30EHWNZ7/8ql4RRsM2 grjhexoDMYhIVhvu070dTPnH8WcQW7zorHQDQA5xpnYJpfr1vUYEgZ4SGreutDgKkDBqEyMWhLFbG zs7KrJUHWGwWk0YrL0fiHDEw/sSeg4206JQVNonbBW+FsjhY09aL9seyGEefvW9rSTpG4LVh5dK/g O0ehSzzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sq8yr-00000003iBa-0QUC; Mon, 16 Sep 2024 10:29:17 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sq8xk-00000003i36-0t7M for linux-arm-kernel@lists.infradead.org; Mon, 16 Sep 2024 10:28:10 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726482485; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=yMOO+5zuP47cm2PSmBG0SvJ4q2L6HUZ6VPVcAFdwe5s=; b=FTjvaNch315i0eLxUIlFo/iDIHkRYnnz8kwF19hMYhnUmpkK/g5SaGiq9yGWe/cARxvVBI 2vANcUHPMVqWD2FimCNJe7cnRSyFSWoedxAq3YXNUjm+KAANlU/fn92+PxSNqxFP+RrWHD IZBLwsZ6oDGSr/1p1Wc+vWvWoNAK8yI= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-146-XEWiKj66NRy6m1-Aa4Za4Q-1; Mon, 16 Sep 2024 06:28:02 -0400 X-MC-Unique: XEWiKj66NRy6m1-Aa4Za4Q-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 84C871953944; Mon, 16 Sep 2024 10:27:59 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.82]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id AB17530001AB; Mon, 16 Sep 2024 10:27:54 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 16 Sep 2024 12:27:47 +0200 (CEST) Date: Mon, 16 Sep 2024 12:27:41 +0200 From: Oleg Nesterov To: Steven Rostedt , Masami Hiramatsu , Catalin Marinas , Will Deacon , Puranjay Mohan , Mark Rutland , Mark Brown , Kalesh Singh , chenqiwu Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: arm64: stacktrace: WARN_ON(state->common.pc == orig_pc) in kunwind_recover_return_address() Message-ID: <20240916102741.GA13899@redhat.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240916_032808_345125_69C4BD17 X-CRM114-Status: GOOD ( 11.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org I don't know the details but people report that kunwind_recover_return_address() hits this warning. I know absolutely nothing about arm64 or kernel/trace/fgraph.c, but at first glance this code looks broken: kunwind_recover_return_address: ... orig_pc = ftrace_graph_ret_addr(state->task, NULL, state->common.pc, (void *)state->common.fp); if (WARN_ON_ONCE(state->common.pc == orig_pc)) ftrace_graph_ret_addr: ... if (!idx) return ret; given that kunwind_recover_return_address() passes idx == NULL to ftrace_graph_ret_addr(), it should always return ret == state->common.pc ? Perhaps this connects to 29c1c24a27 ("function_graph: Fix up ftrace_graph_ret_addr()") and I have no idea if something like the patch below makes any sense. Oleg. --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -106,7 +106,8 @@ kunwind_recover_return_address(struct kunwind_state *state) if (state->task->ret_stack && (state->common.pc == (unsigned long)return_to_handler)) { unsigned long orig_pc; - orig_pc = ftrace_graph_ret_addr(state->task, NULL, + orig_pc = ftrace_graph_ret_addr(state->task, + &state->task->curr_ret_stack, state->common.pc, (void *)state->common.fp); if (WARN_ON_ONCE(state->common.pc == orig_pc))