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[97.41.130.233]) by smtp.gmail.com with ESMTPSA id v20sm24623076pfe.118.2019.04.04.10.56.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Apr 2019 10:56:29 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault Date: Thu, 4 Apr 2019 11:11:26 -0600 Message-Id: <8876301F-C720-4DFD-8D01-F9C526E21A10@amacapital.net> References: <20190404013956.GA3365@cisco> <20190404154727.GA14030@cisco> Cc: Tycho Andersen , Andy Lutomirski , Khalid Aziz , Juerg Haefliger , 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 , "Kirill A. Shutemov" , Christoph Hellwig , steven.sistare@oracle.com, Laura Abbott , 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, "Serge E. Hallyn" , iommu@lists.linux-foundation.org, X86 ML , linux-arm-kernel , "open list:DOCUMENTATION" , LKML , Linux-MM , LSM List , Khalid Aziz In-Reply-To: To: Thomas Gleixner X-Mailer: iPhone Mail (16D57) 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 Apr 4, 2019, at 10:28 AM, Thomas Gleixner wrote: >=20 >> On Thu, 4 Apr 2019, Tycho Andersen wrote: >> leaq -PTREGS_SIZE(%rax), %rsp >> UNWIND_HINT_FUNC sp_offset=3DPTREGS_SIZE >>=20 >> + /* >> + * If we oopsed in an interrupt handler, interrupts may be off. Let'= s turn >> + * them back on before going back to "normal" code. >> + */ >> + sti >=20 > That breaks the paravirt muck and tracing/lockdep. >=20 > ENABLE_INTERRUPTS() is what you want plus TRACE_IRQ_ON to keep the tracer > and lockdep happy. >=20 >=20 I=E2=80=99m sure we=E2=80=99ll find some other thing we forgot to reset even= tually, so let=E2=80=99s do this in C. Change the call do_exit to call __fi= nish_rewind_stack_do_exit and add the latter as a C function that does local= _irq_enable() and do_exit().=