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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 36FFCC43461 for ; Mon, 14 Sep 2020 20:24:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D688E208DB for ; Mon, 14 Sep 2020 20:24:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="3c8skZ59"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="U2fMCUyQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726245AbgINUYc (ORCPT ); Mon, 14 Sep 2020 16:24:32 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35764 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726221AbgINUXD (ORCPT ); Mon, 14 Sep 2020 16:23:03 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1600114979; 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: in-reply-to:in-reply-to:references:references; bh=P0wfLZ0uYBLfAv6Tql/b2JqWp+4rVtLisrjtqK8ycp4=; b=3c8skZ59/xzAZZZp4Z+4ovwLPez/sz6q0DBzv6UMDN/DlDIoE+fRGmGlTzzgqa2rboXGRd kKSVAj5iZ5CAlIdiIkQWLVqOSlt4kJb4Alend5up+cyKKPfsXm7Am0cywiR+fqOaVrCqSX CRkUUuL8V3bk2Rakj/e5AaXGVCwN+26Eu/nyl2X2hOjXUdGeKWBbG8C/HfS7HHcwm5TD6i DI2+jUCaYNKM/XmDyaQovGgzjoy43OyqD6rm1/qFtgb+FcqN4fILUTRVN43BsVtm1JfWE+ IA0DJxuUBS0Nyv06qLU+t68uGxIFCLa/7cn3xJ4HS7J70wI4nlLHeGTH+7IKMA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1600114979; 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: in-reply-to:in-reply-to:references:references; bh=P0wfLZ0uYBLfAv6Tql/b2JqWp+4rVtLisrjtqK8ycp4=; b=U2fMCUyQntR2d4BUcbWISYNvXjgqMmN5EdqANELCzmmxUE0BASxc0DX3BdoywLRG+A4fZl ocGojm8RQivNPuAQ== To: Kees Cook Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, syzbot , syzkaller-bugs@googlegroups.com, Andy Lutomirski , Peter Zijlstra Subject: Re: WARNING in syscall_exit_to_user_mode In-Reply-To: <202009141304.811BAC4A0@keescook> References: <00000000000018a47605af074c7d@google.com> <202009121050.0D9CAB95@keescook> <87sgblpi4l.fsf@nanos.tec.linutronix.de> <202009141304.811BAC4A0@keescook> Date: Mon, 14 Sep 2020 22:22:59 +0200 Message-ID: <87a6xsp0po.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 14 2020 at 13:06, Kees Cook wrote: > On Sun, Sep 13, 2020 at 09:54:34PM +0200, Thomas Gleixner wrote: >> On Sat, Sep 12 2020 at 10:52, Kees Cook wrote: >> >> ------------[ cut here ]------------ >> >> syscall 56 left IRQs disabled >> > >> > This WARN appears reachable. :) >> >> The above is hardly a problem of the new entry code. It's just detecting >> the wreckage... > > Oh, well that's actually even better! :) Of course I can't reproduce here ... >> > I also see on the dashboard these other problems with the new entry >> > code: >> >> > https://syzkaller.appspot.com/bug?extid=d4336c84ed0099fdbe47 >> >> This one is also just the messenger. That's the >> >> lockdep_assert_irqs_disabled(); >> >> in irqentry_exit() if I'm reading the reports correctly. That's a #PF >> returning with interrupts enabled for whatever weird reason. Let me >> stare at that... > > Cool; thanks. No idea so far. >> > https://syzkaller.appspot.com/bug?extid=c4af95386364bc59b13e >> >> This one is not a new entry code problem either: >> [...] >> The new entry code is just in the stack trace because that task was >> preempted after a timer interrupt. > > This seems a bit like the first issue: it's just getting noticed now? IIRC, I've seen such reports on older kernels as well, but not with the new entry code in the traces. Thanks, tglx