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 X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DEA2C433E0 for ; Mon, 3 Aug 2020 12:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ABF82076E for ; Mon, 3 Aug 2020 12:33:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596457990; bh=KP2S6zjMVIV//HHt0ckkmTyuYNbrWQFsrRLKQQLWScM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Xd8/25xqBGdDV99Ze2XZVScRhzhnxY25r+r+pOpqleAtf9rp05Miljwg2QOA1hOow FRGBqXW8VXgAHKy5bU7ayRg23S+9hrBpbvcvsVNHH7RBr1p5O4r9a78ITmDoy+fGN2 +nVNKnWH8s3ecYrskehpYqkvdO80FOeZ9pEkmoTI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728948AbgHCMdI (ORCPT ); Mon, 3 Aug 2020 08:33:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:32900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728608AbgHCMdF (ORCPT ); Mon, 3 Aug 2020 08:33:05 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E267B2076B; Mon, 3 Aug 2020 12:33:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596457984; bh=KP2S6zjMVIV//HHt0ckkmTyuYNbrWQFsrRLKQQLWScM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kp4RF5e6c4AYx0kMN8O4UyRTljlgAvRHTt272KbNkLR/8MEm7sp0T7TM4yY8e2vDg 1aJYLuz0uZamTmBt75kc7L6eIFnyhOqUp+modpwVmBUKyvKT7TUTemC2ML+LdvZL2o 2ree9cpM+LCSTAdKLipHI+ikpgq+hlb30DbTG5tc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wang ShaoBo , Josh Poimboeuf , Thomas Gleixner , Sasha Levin Subject: [PATCH 4.19 52/56] x86/unwind/orc: Fix ORC for newly forked tasks Date: Mon, 3 Aug 2020 14:20:07 +0200 Message-Id: <20200803121852.874529785@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200803121850.306734207@linuxfoundation.org> References: <20200803121850.306734207@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josh Poimboeuf [ Upstream commit 372a8eaa05998cd45b3417d0e0ffd3a70978211a ] The ORC unwinder fails to unwind newly forked tasks which haven't yet run on the CPU. It correctly reads the 'ret_from_fork' instruction pointer from the stack, but it incorrectly interprets that value as a call stack address rather than a "signal" one, so the address gets incorrectly decremented in the call to orc_find(), resulting in bad ORC data. Fix it by forcing 'ret_from_fork' frames to be signal frames. Reported-by: Wang ShaoBo Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Tested-by: Wang ShaoBo Link: https://lkml.kernel.org/r/f91a8778dde8aae7f71884b5df2b16d552040441.1594994374.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin --- arch/x86/kernel/unwind_orc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 2701b370e58fe..1d264ba1e56d1 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -420,8 +420,11 @@ bool unwind_next_frame(struct unwind_state *state) /* * Find the orc_entry associated with the text address. * - * Decrement call return addresses by one so they work for sibling - * calls and calls to noreturn functions. + * For a call frame (as opposed to a signal frame), state->ip points to + * the instruction after the call. That instruction's stack layout + * could be different from the call instruction's layout, for example + * if the call was to a noreturn function. So get the ORC data for the + * call instruction itself. */ orc = orc_find(state->signal ? state->ip : state->ip - 1); if (!orc) @@ -634,6 +637,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, state->sp = task->thread.sp; state->bp = READ_ONCE_NOCHECK(frame->bp); state->ip = READ_ONCE_NOCHECK(frame->ret_addr); + state->signal = (void *)state->ip == ret_from_fork; } if (get_stack_info((unsigned long *)state->sp, state->task, -- 2.25.1