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[198.145.29.99]) by mx.google.com with ESMTPS id e5si14942279pgk.150.2019.04.03.17.13.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 03 Apr 2019 17:13:16 -0700 (PDT) Received-SPF: pass (google.com: domain of luto@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=NwsoRh6B; spf=pass (google.com: domain of luto@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=luto@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) (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 195AF21920 for ; Thu, 4 Apr 2019 00:13:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554336796; bh=GGJRHe3KYjcQNLG8aTrg3U7oNNkXkzmOgdq/8cfXfjw=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=NwsoRh6BPwrwAzfdiQ9XHSWmrJWT625FhIjKOop41FfRt21WUy1yDf/PYmmoiltJk 6ylzQm7C87ZY91BMa7+qWjjJPp6tbFj+t5d5Ou/IrW/Jf4/0ufCgYfsGNkVyZUKM1Q hmVEB+Hte3ih2OqzssBNx2VAqmc+eHgvOvmmnwsM= Received: by mail-wm1-f41.google.com with SMTP id z11so838981wmi.0 for ; Wed, 03 Apr 2019 17:13:16 -0700 (PDT) X-Received: by 2002:a1c:99d5:: with SMTP id b204mr1752292wme.95.1554336787336; Wed, 03 Apr 2019 17:13:07 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andy Lutomirski Date: Wed, 3 Apr 2019 17:12:56 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault To: Khalid Aziz Cc: Juerg Haefliger , Tycho Andersen , jsteckli@amazon.de, Andi Kleen , liran.alon@oracle.com, Kees Cook , Konrad Rzeszutek Wilk , deepa.srinivasan@oracle.com, chris hyser , Tyler Hicks , "Woodhouse, David" , Andrew Cooper , Jon Masters , Boris Ostrovsky , kanth.ghatraju@oracle.com, Joao Martins , Jim Mattson , pradeep.vincent@oracle.com, John Haxby , Thomas Gleixner , "Kirill A. Shutemov" , Christoph Hellwig , steven.sistare@oracle.com, Laura Abbott , Andrew Lutomirski , Dave Hansen , Peter Zijlstra , Aaron Lu , Andrew Morton , alexander.h.duyck@linux.intel.com, Amir Goldstein , Andrey Konovalov , aneesh.kumar@linux.ibm.com, anthony.yznaga@oracle.com, Ard Biesheuvel , Arnd Bergmann , arunks@codeaurora.org, Ben Hutchings , Sebastian Andrzej Siewior , Borislav Petkov , brgl@bgdev.pl, Catalin Marinas , Jonathan Corbet , cpandya@codeaurora.org, Daniel Vetter , Dan Williams , Greg KH , Roman Gushchin , Johannes Weiner , "H. Peter Anvin" , Joonsoo Kim , James Morse , Jann Horn , Juergen Gross , Jiri Kosina , James Morris , Joe Perches , Souptick Joarder , Joerg Roedel , Keith Busch , Konstantin Khlebnikov , Logan Gunthorpe , marco.antonio.780@gmail.com, Mark Rutland , Mel Gorman , Michal Hocko , Michal Hocko , Mike Kravetz , Ingo Molnar , "Michael S. Tsirkin" , Marek Szyprowski , Nicholas Piggin , osalvador@suse.de, "Paul E. McKenney" , pavel.tatashin@microsoft.com, Randy Dunlap , richard.weiyang@gmail.com, Rik van Riel , David Rientjes , Robin Murphy , Steven Rostedt , Mike Rapoport , Sai Praneeth Prakhya , "Serge E. Hallyn" , Steve Capper , thymovanbeers@gmail.com, Vlastimil Babka , Will Deacon , Matthew Wilcox , yang.shi@linux.alibaba.com, yaojun8558363@gmail.com, Huang Ying , zhangshaokun@hisilicon.com, iommu@lists.linux-foundation.org, X86 ML , linux-arm-kernel , "open list:DOCUMENTATION" , LKML , Linux-MM , LSM List , Khalid Aziz Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 3, 2019 at 10:36 AM Khalid Aziz wrote: > > From: Tycho Andersen > > Oopsing might kill the task, via rewind_stack_do_exit() at the bottom, and > that might sleep: > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 9d5c75f02295..7891add0913f 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -858,6 +858,12 @@ no_context(struct pt_regs *regs, unsigned long error_code, > /* Executive summary in case the body of the oops scrolled away */ > printk(KERN_DEFAULT "CR2: %016lx\n", address); > > + /* > + * We're about to oops, which might kill the task. Make sure we're > + * allowed to sleep. > + */ > + flags |= X86_EFLAGS_IF; > + > oops_end(flags, regs, sig); > } > NAK. If there's a bug in rewind_stack_do_exit(), please fix it in rewind_stack_do_exit().