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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 0CC91C433E0 for ; Tue, 9 Jun 2020 00:40:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB9C420737 for ; Tue, 9 Jun 2020 00:40:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591663217; bh=amJlntM7cL51BUjWOmIJKS2PIvEibkIaWrfHuN4gSMs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vLhJHOI4iU4VFUn5HmNXcUGwjMjDVTeOGhPEaOuVRWXj7Y/vEQ5/ZUB3KdU/GCWZJ EGVtO6sDsDSWLmMxuvZepbpJSWoLt9FfyT4zikjaE82EBv8WbyLNaeZImQgYrzet4A EuRNooHBOpIK3XYBER5nkS8168PU1xrMSO517TCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729225AbgFHXNF (ORCPT ); Mon, 8 Jun 2020 19:13:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:60934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729217AbgFHXND (ORCPT ); Mon, 8 Jun 2020 19:13:03 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 32EBC20897; Mon, 8 Jun 2020 23:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591657982; bh=amJlntM7cL51BUjWOmIJKS2PIvEibkIaWrfHuN4gSMs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vfe0iTVydxwryS8pausQZSLEPE3UWcbIxynFHUHQZhS5AYGa6Udx3FuRPduJgMADq rPh4I7vGp7gUGX7KKzN8fESyJ8UveQDcotmftnNaMrqlIACfqGK9JUz2fxILk7K+VS INK5IvsD73Cf2xZErriw2y8fE0g19F3BBonTy+CE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Josh Poimboeuf , Pavel Machek , Peter Zijlstra , Greg Kroah-Hartman Subject: [PATCH AUTOSEL 5.6 043/606] x86/unwind/orc: Fix error handling in __unwind_start() Date: Mon, 8 Jun 2020 19:02:48 -0400 Message-Id: <20200608231211.3363633-43-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josh Poimboeuf commit 71c95825289f585014fe9741b051d32a7a916680 upstream. The unwind_state 'error' field is used to inform the reliable unwinding code that the stack trace can't be trusted. Set this field for all errors in __unwind_start(). Also, move the zeroing out of the unwind_state struct to before the ORC table initialization check, to prevent the caller from reading uninitialized data if the ORC table is corrupted. Fixes: af085d9084b4 ("stacktrace/x86: add function for detecting reliable stack traces") Fixes: d3a09104018c ("x86/unwinder/orc: Dont bail on stack overflow") Fixes: 98d0c8ebf77e ("x86/unwind/orc: Prevent unwinding before ORC initialization") Reported-by: Pavel Machek Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/d6ac7215a84ca92b895fdd2e1aa546729417e6e6.1589487277.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/unwind_orc.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 80537dcbddef..9414f02a55ea 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -611,23 +611,23 @@ EXPORT_SYMBOL_GPL(unwind_next_frame); void __unwind_start(struct unwind_state *state, struct task_struct *task, struct pt_regs *regs, unsigned long *first_frame) { - if (!orc_init) - goto done; - memset(state, 0, sizeof(*state)); state->task = task; + if (!orc_init) + goto err; + /* * Refuse to unwind the stack of a task while it's executing on another * CPU. This check is racy, but that's ok: the unwinder has other * checks to prevent it from going off the rails. */ if (task_on_another_cpu(task)) - goto done; + goto err; if (regs) { if (user_mode(regs)) - goto done; + goto the_end; state->ip = regs->ip; state->sp = regs->sp; @@ -660,6 +660,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, * generate some kind of backtrace if this happens. */ void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp); + state->error = true; if (get_stack_info(next_page, state->task, &state->stack_info, &state->stack_mask)) return; @@ -685,8 +686,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, return; -done: +err: + state->error = true; +the_end: state->stack_info.type = STACK_TYPE_UNKNOWN; - return; } EXPORT_SYMBOL_GPL(__unwind_start); -- 2.25.1