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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 0CE61C43381 for ; Thu, 21 Mar 2019 09:02:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB102218D4 for ; Thu, 21 Mar 2019 09:02:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ofdQOeNm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728079AbfCUJCv (ORCPT ); Thu, 21 Mar 2019 05:02:51 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:33632 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727859AbfCUJCu (ORCPT ); Thu, 21 Mar 2019 05:02:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=7xrTOIEHJHDFjEhBP7mEM8RRVlFCfaVww58exeZTQNw=; b=ofdQOeNmKyMLYgzqboB6alj4Q 3bA9QIQYZEBDm0etd7+8mkeBeP1ZloG8VtiO5M+1A/+hm5X4vxneriDAoTYkwn3+dsZMMw+n0+zt7 Ln4gXCl6YVsnKMoWGCCrsueo5nO9hvSmUzLROHh1raHs8jA+nheg/HoF8ey/EuXMkQYgempJZY6IJ YFQqQ//1eTRqDtiE6gNPjAaZbtEUq0N7OS2hPy36UJTVvT7GYgnQnBrznui68mGM4V5/zrc46wDjU K4x9nmRq0lyobB2yygk3NsTtjQ8amuIUWYbkldBQWkcLn75qf3Nf6RwylPvcG+OUItn8aiV4zfeCn uGna/6NBw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h6tb1-0004SQ-Nj; Thu, 21 Mar 2019 09:02:43 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 589752391A9A9; Thu, 21 Mar 2019 10:02:41 +0100 (CET) Date: Thu, 21 Mar 2019 10:02:41 +0100 From: Peter Zijlstra To: Steven Rostedt Cc: LKML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Joel Fernandes , He Zhe , Linus Torvalds Subject: Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry Message-ID: <20190321090241.GL6521@hirez.programming.kicks-ass.net> References: <20190320221534.165ab87b@oasis.local.home> <20190321083317.GL6058@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190321083317.GL6058@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 21, 2019 at 09:33:17AM +0100, Peter Zijlstra wrote: I'm thinking this problem wasn't new. > idtentry page_fault do_page_fault has_error_code=1 > call error_entry > TRACE_IRQS_OFF > call trace_hardirqs_off* > > # modifies CR2 CALL_enter_from_user_mode __context_tracking_exit() trace_user_exit(0) #PF > call do_page_fault > address = read_cr2(); /* whoopsie */ And that also isn't fixed by your patch. I'm trying to make idtentry put cr2 in rdx, such that do_page_fault() takes address as a 3rd argument, but I'm still fighting that context tracking nonsense.