From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752002AbdH2JXF convert rfc822-to-8bit (ORCPT ); Tue, 29 Aug 2017 05:23:05 -0400 Received: from mout.gmx.net ([212.227.15.15]:54172 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691AbdH2JXC (ORCPT ); Tue, 29 Aug 2017 05:23:02 -0400 Message-ID: <1503998491.8323.23.camel@gmx.de> Subject: Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement fast refcount overflow protection From: Mike Galbraith To: Ingo Molnar Cc: Kees Cook , LKML , Ingo Molnar , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , Linus Torvalds , Elena Reshetova , Arnd Bergmann , "H. Peter Anvin" Date: Tue, 29 Aug 2017 11:21:31 +0200 In-Reply-To: <20170829085841.gwmdbncrm6txcezt@gmail.com> References: <1503996623.8323.20.camel@gmx.de> <20170829085841.gwmdbncrm6txcezt@gmail.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K0:KVD3ltbON3dB1yYjYl2m/ybScC6vjZTTUJtvsizwdye70YE81zo EuoOeGmfpfPca7BDmhHXHxeBluvz4KXGcyGsHKy1fnK5D+OwXKfRRDSVuPzpdpvkqqEKU8y GSs4LgWUjioKO4AwKmsuqVf/M0llOcLcrUWpaRxgI0jOp46z4c8+EFNBTSJUi2kI+U2nkgg tuEdzzMs47+Xce0tyezWQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:ExBYxYsX0Js=:Uihs8PxaWg0kiU15rGCI29 5Mv5bc0aSsmLUfLIUc+1VtwXnBLK2mrJpm6zsowhgtuKn1geo9H11CqA2E+jUuYtZbvSa8TWn JhAMl/E4160CJS4IPd1BLqdRkFvB3BSvXt7gQZ2dGxW7YKCVXwi6jr4xPGxQtGEXJleRHVXm1 AXH2fef8f+IgMg0TjlpLcnspUiqBHIM7cjfiy6WX6cug9n/uKwFa/j9M9kvv4IiOUMuqIUK9i Hty7zmlOP86ZYQrmFzISR9a/ioEdUFzLekBbnk37v8OcKoWryZDt5s8pMfX9ugzzlkDe6cMge JSmgXdZcGDntx7AuM74NGTHiaf9fUCD06SMS2OV5D9R0P1i/MP4s62GKjvdzfPD0Fi28m78uC D+UR5CsoCIAXCja9yiznRpQgtLESfDJ1Az6U2PSDfcabgoZ+2nO6VG/9V1UsVojy5Qttbl1Jr xRGyb2xL3UpPzoXdf/7/lK8iWMRCUnL4p4qEm4d3hO+XxZi88Hni4aUdQUtlPA0U4T6m4SCHh BN/W07nssyUV5sYZpC5xaVT6hr8WYQmSZ1qMNo0uXtBOwcaXT7pTP7Xx+ISltPGBG+tRSPpfQ NP8TEWBKGVS7/s6oVgZT2owrnYsE/E/UUyU08xB3XLKBnsA0NdGQZFYOG3CFUfZr+JDJdZU8A WYBAkRNch/FWurDCFjsSPcOGgfp1QNRyQkIlIqZkc/uPRxrpwFDjTwGhV+b9XQvhJ0zZoT1QI uDBNvxY8OMbnLwoAjSpbLN2sGWHr/b+JUV7FWQTZQBKK3yWTwx1BT+oSy9Z29xNft05m/lEvB Rpnl78x3mJdIIn+8hSRrqiQBFXjYUIvkYKkpFNoosLTC0OuwGI= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2017-08-29 at 10:58 +0200, Ingo Molnar wrote: > * Mike Galbraith wrote: > > > Greetings, > > > > Take 2 of KVM bisect as you work fingered $subject.  Take 1 was stymied > > by build dependencies (aa5d1b81, df340524) which I foolishly tried to > > skip, leading git bisect to end up handing me a list of commits that > > might be busted.  During take 2, I added those two as required. > > > > Symptom is a few splats as below, with box finally hanging.  Network > > comes up, but neither ssh nor console login is possible. > > Just to double check, does the patch below also cure the regression? > If we don't find the bug it might be safer than a full revert. I reverted it, and vbox now boots.  Should I still try the below? > > Thanks, > > Ingo > > arch/x86/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index d04809921993..3b83ef8f1e9b 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -55,7 +55,7 @@ config X86 > select ARCH_HAS_KCOV if X86_64 > select ARCH_HAS_MMIO_FLUSH > select ARCH_HAS_PMEM_API if X86_64 > - select ARCH_HAS_REFCOUNT > +# select ARCH_HAS_REFCOUNT > select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 > select ARCH_HAS_SET_MEMORY > select ARCH_HAS_SG_CHAIN