From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [PATCH -v5 6/5] context_tracking: fix exception_enter when already in IN_KERNEL Date: Thu, 12 Feb 2015 12:48:51 -0500 Message-ID: <54DCE783.6080200@redhat.com> References: <1423600074-2907-1-git-send-email-riel@redhat.com> <20150211144319.2a0c29d6@cuia.bos.redhat.com> <20150212154232.GE18363@lerouge> <54DCCAFE.7080206@redhat.com> <20150212170002.GH18363@lerouge> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: paulmck@linux.vnet.ibm.com, luto@amacapital.net, will.deacon@arm.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mtosatti@redhat.com, borntraeger@de.ibm.com, lcapitulino@redhat.com, pbonzini@redhat.com To: Frederic Weisbecker Return-path: In-Reply-To: <20150212170002.GH18363@lerouge> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/12/2015 12:00 PM, Frederic Weisbecker wrote: > On Thu, Feb 12, 2015 at 10:47:10AM -0500, Rik van Riel wrote: >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >> >> On 02/12/2015 10:42 AM, Frederic Weisbecker wrote: >>> On Wed, Feb 11, 2015 at 02:43:19PM -0500, Rik van Riel wrote: >>>> If exception_enter happens when already in IN_KERNEL state, >>>> the code still calls context_tracking_exit, which ends up in >>>> rcu_eqs_exit_common, which explodes with a WARN_ON when it >>>> is called in a situation where dynticks are not enabled. >>> >>> Fortunately context_tracking_exit() already has a current_state >>> == IN_KERNEL check so this shouldn't be a problem. >> >> No, it had a hard-coded "current_state == IN_USER" check, which >> is very close, but ... >> >> ... I replaced that with a state argument, and forgot to ensure >> that it never gets called with state == IN_KERNEL. This patch >> fixes that. > > Ah that's right! Well I'm going to merge this patch to 1/5 then to > avoid breaking bisection. Thank you, Frederic! - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJU3OeDAAoJEM553pKExN6D7BsIAJ8CKC73jQ8T5Dqa/tlHV7Db QFSJdpxP+7jCZwssehgpjpxCwtJ0UvGgle5OwX/POUhmagHxHmxVydOBz+xfYdBr UuGkEl5TL+oyoMUr80Q4RTnJSZN08zi+THqiv33tyPUj6cNiycBZAuho3ELTRNOA bRcHrMW+xd95uqoung7dSKrgA2jcym3+umNGnQb0gniraqcNLAmWs+jfAO8yZLJg vk8bIKed6epQ3n6gcdYe0A28cLOuBvjEs5JNcEPxujY/349sjitKR2pLQ6HsfHLV frlKsh7qQIRtoUJLO9ZBBDtGrmThwBwH8rw+GcVR8zviPNvV4IRrx47VBcHDWjc= =mwFO -----END PGP SIGNATURE-----