From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964852AbbCPQsn (ORCPT ); Mon, 16 Mar 2015 12:48:43 -0400 Received: from mail.skyhub.de ([78.46.96.112]:56041 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933230AbbCPQsl (ORCPT ); Mon, 16 Mar 2015 12:48:41 -0400 Date: Mon, 16 Mar 2015 17:47:07 +0100 From: Borislav Petkov To: dvlasenk@redhat.com Cc: linux-tip-commits@vger.kernel.org, linux-kernel@vger.kernel.org, keescook@chromium.org, ast@plumgrid.com, fweisbec@gmail.com, oleg@redhat.com, tglx@linutronix.de, torvalds@linux-foundation.org, hpa@zytor.com, mingo@kernel.org, wad@chromium.org, rostedt@goodmis.org, dvlasenk@redhat.com Subject: Re: [tip:x86/asm] x86/asm/entry/64: Remove unused thread_struct:: usersp Message-ID: <20150316164707.GB23015@pd.tnic> References: <1425984307-2143-2-git-send-email-dvlasenk@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 16, 2015 at 05:05:53AM -0700, tip-bot for Denys Vlasenko wrote: > Commit-ID: 245214a155c711764b3853189441c9f8aeb058b3 > Gitweb: http://git.kernel.org/tip/245214a155c711764b3853189441c9f8aeb058b3 > Author: Denys Vlasenko > AuthorDate: Tue, 10 Mar 2015 11:45:07 +0100 > Committer: Ingo Molnar > CommitDate: Tue, 10 Mar 2015 13:56:11 +0100 > > x86/asm/entry/64: Remove unused thread_struct::usersp > > All manipulations of PER_CPU(old_rsp) in C code are removed: > it is not used on SYSRET return, so storing anything there is > pointless. > > This also allows us to get rid of thread_struct::usersp, > which was needed only to set PER_CPU(old_rsp) for correct > return from fork/clone. > > Tweak a few comments as well: we no longer have "partial stack frame", > ever. > > Signed-off-by: Denys Vlasenko > Cc: Alexei Starovoitov > Cc: Borislav Petkov > Cc: Frederic Weisbecker > Cc: H. Peter Anvin > Cc: Kees Cook > Cc: Linus Torvalds > Cc: Oleg Nesterov > Cc: Steven Rostedt > Cc: Will Drewry > Link: http://lkml.kernel.org/r/1425984307-2143-2-git-send-email-dvlasenk@redhat.com > Signed-off-by: Ingo Molnar So this patch is causing all kinds of segfaults when booting my kvm guest here, see below. Reverting it makes the segfaults go away but from looking at the patch, I have no idea why it would even cause those segfaults. [ 5.285547] kmod[1316]: segfault at 738c08 ip 0000000000738c08 sp 00007ffdb6079c68 error 15 [ 9.537606] tput[2716]: segfault at 0 ip (null) sp 00007fffffffdbd0 error 14 in tput[400000+3000] ^^^^^^^^^^^^^^^^^ Looks like rIP has went off somewhere in the weeds. Hmmm... [ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp 00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000] [ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp 00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000] [ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp 00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000] [ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp 00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000] [ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp 00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000] [ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp 00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000] [ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp 00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000] [ 5.607611] sed[1350]: segfault at 7ffddd4a4bf0 ip 00007ff24a11fafc sp 00007ffddd4a4bf0 error 4 in libc-2.13.so[7ff24a050000+182000] [ 9.820987] update-exim4.co[2755]: segfault at 7ffff79ab000 ip 00007ffff79ab000 sp 00007fffffffe278 error 15 [ 10.580362] tput[3060]: segfault at 7ffff6376cb0 ip 00007ffff7df3422 sp 00007ffff6376cb0 error 4 in ld-2.13.so[7ffff7ddd000+20000] [ 5.607611] sed[1350]: segfault at 7ffddd4a4bf0 ip 00007ff24a11fafc sp 00007ffddd4a4bf0 error 4 in libc-2.13.so[7ff24a050000+182000] [ 9.820987] update-exim4.co[2755]: segfault at 7ffff79ab000 ip 00007ffff79ab000 sp 00007fffffffe278 error 15 [ 10.580362] tput[3060]: segfault at 7ffff6376cb0 ip 00007ffff7df3422 sp 00007ffff6376cb0 error 4 in ld-2.13.so[7ffff7ddd000+20000] -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --