From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751111AbbFLIzh (ORCPT ); Fri, 12 Jun 2015 04:55:37 -0400 Received: from terminus.zytor.com ([198.137.202.10]:34152 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbbFLIzc (ORCPT ); Fri, 12 Jun 2015 04:55:32 -0400 Date: Fri, 12 Jun 2015 01:54:35 -0700 From: tip-bot for Dave Hansen Message-ID: Cc: mingo@kernel.org, dvlasenk@redhat.com, bp@alien8.de, luto@amacapital.net, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, brgerst@gmail.com Reply-To: hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, brgerst@gmail.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, bp@alien8.de, luto@amacapital.net, dvlasenk@redhat.com, mingo@kernel.org, dave.hansen@linux.intel.com In-Reply-To: <20150611193400.2E0B00DB@viggo.jf.intel.com> References: <20150611193400.2E0B00DB@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/fpu] x86/fpu: Fix double-increment in setup_xstate_features() Git-Commit-ID: a8424003679e90b9952e20adcd1ff1560d9dd3e9 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a8424003679e90b9952e20adcd1ff1560d9dd3e9 Gitweb: http://git.kernel.org/tip/a8424003679e90b9952e20adcd1ff1560d9dd3e9 Author: Dave Hansen AuthorDate: Thu, 11 Jun 2015 12:34:00 -0700 Committer: Ingo Molnar CommitDate: Fri, 12 Jun 2015 10:48:12 +0200 x86/fpu: Fix double-increment in setup_xstate_features() I noticed that my MPX tracepoints were producing garbage for the lower and upper bounds: mpx_bounds_register_exception: address referenced: 0x00007fffffffccb7 bounds: lower: 0x0 ~upper: 0xffffffffffffffff mpx_bounds_register_exception: address referenced: 0x00007fffffffccbf bounds: lower: 0x0 ~upper: 0xffffffffffffffff This is, of course, bogus because 0x00007fffffffccbf is *within* the bounds. I assumed that my instruction decoder was bad and went looking at it. But I eventually realized that I was getting a '0' offset back from xstate_offsets[BNDREGS]. It was being skipped in the initialization, which is obviously bogus, so remove the extra leaf++. This also goes an initializes xstate_offsets/sizes[] to -1 so so that bugs like this will oops instead of silently failing in interesting ways. This was introduced by: 39f1acd ("x86/fpu/xstate: Don't assume the first zero xfeatures zero bit means the end") Signed-off-by: Dave Hansen Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dave@sr71.net Link: http://lkml.kernel.org/r/20150611193400.2E0B00DB@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/xstate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 49d0d9b..62fc001 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -31,7 +31,8 @@ static const char *xfeature_names[] = */ u64 xfeatures_mask __read_mostly; -static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX]; +static unsigned int xstate_offsets[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1}; +static unsigned int xstate_sizes[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1}; static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8]; /* The number of supported xfeatures in xfeatures_mask: */ @@ -187,7 +188,6 @@ static void __init setup_xstate_features(void) xstate_sizes[leaf] = eax; printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %04x, xstate_sizes[%d]: %04x\n", leaf, ebx, leaf, eax); - leaf++; } }