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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 Subject: Re: [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault Message-ID: <20190404013956.GA3365@cisco> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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 03, 2019 at 05:12:56PM -0700, Andy Lutomirski wrote: > 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(). [I trimmed the CC list since google rejected it with E2BIG :)] I guess the problem is really that do_exit() (or really exit_signals()) might sleep. Maybe we should put an irq_enable() at the beginning of do_exit() instead and fix this problem for all arches? Tycho