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_HELO_NONE,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 4B78BC28CC0 for ; Wed, 29 May 2019 17:03:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1758423E96 for ; Wed, 29 May 2019 17:03:37 +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="WefAf3Cm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726304AbfE2RDg (ORCPT ); Wed, 29 May 2019 13:03:36 -0400 Received: from merlin.infradead.org ([205.233.59.134]:37998 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726043AbfE2RDf (ORCPT ); Wed, 29 May 2019 13:03:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=1mK5Smhvmft4JcvDPEMxWC67pAyc4oQ9bkdnZBw20t4=; b=WefAf3Cmu+ntxwjXzgTrWTw1+ DmS8xvC5x60ErHEUn5jj0rUuKGmjSb+fnt78VxRlXy4oW5Zizoqr3FlZfCaLD62UnLvAgmdwAa9ax kYZPrL7zJPXASqXg2SqsyR57N0EMomCKw6pNZrFgfh7Wlpp5FUO6gFAlfAQhA6bNKhRRzExM0Q5Iy CL63Z3VvG2zYe/yslLDz5myjb5n3+MM4yaqaOIKc8jzf+4GK0RDrzsNKGoW115UCEflKh61Wh5IjV NvveowY9GQgLkh7sga4Ls0FEUDiUQmxhUVtUWQHfX0gkTQ/ruySWz+rQv7b32qb1Bkxa+u6Ws5Qvf y+zEiljIg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hW1yt-0008A1-17; Wed, 29 May 2019 17:03:15 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C4080201B8CFF; Wed, 29 May 2019 19:03:13 +0200 (CEST) Date: Wed, 29 May 2019 19:03:13 +0200 From: Peter Zijlstra To: Mark Rutland Cc: Will Deacon , Young Xiao <92siuyang@gmail.com>, linux@armlinux.org.uk, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, kan.liang@linux.intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, ravi.bangoria@linux.vnet.ibm.com, mpe@ellerman.id.au, acme@redhat.com, eranian@google.com, fweisbec@gmail.com, jolsa@redhat.com Subject: Re: [PATCH] perf: Fix oops when kthread execs user process Message-ID: <20190529170313.GE2623@hirez.programming.kicks-ass.net> References: <20190529091733.GA4485@fuggles.cambridge.arm.com> <20190529101042.GN2623@hirez.programming.kicks-ass.net> <20190529102022.GC4485@fuggles.cambridge.arm.com> <20190529125557.GU2623@hirez.programming.kicks-ass.net> <20190529130521.GA11023@fuggles.cambridge.arm.com> <20190529132515.GW2623@hirez.programming.kicks-ass.net> <20190529143510.GA11154@fuggles.cambridge.arm.com> <20190529161955.GZ2623@hirez.programming.kicks-ass.net> <20190529162435.GM31777@lakrids.cambridge.arm.com> <20190529163854.GN31777@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190529163854.GN31777@lakrids.cambridge.arm.com> 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 Wed, May 29, 2019 at 05:38:54PM +0100, Mark Rutland wrote: > Sorry for the noise. n/p, confusion happens :-) > Generally speaking though, if we ever task task_pt_regs() of an idle > task we'll get junk, and user_mode() could be true. Agreed, but we're not doing that.