Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758430AbYGQDRb (ORCPT ); Wed, 16 Jul 2008 23:17:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753794AbYGQDRX (ORCPT ); Wed, 16 Jul 2008 23:17:23 -0400 Received: from tomts16.bellnexxia.net ([209.226.175.4]:59448 "EHLO tomts16-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753514AbYGQDRX (ORCPT ); Wed, 16 Jul 2008 23:17:23 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AugEAKtUfkhMRKxB/2dsb2JhbACBWq5l Date: Wed, 16 Jul 2008 23:17:21 -0400 From: Mathieu Desnoyers To: Ingo Molnar Cc: Steven Rostedt , linux-kernel@vger.kernel.org Subject: [PATCH ftrace.git] Immedate Values Optimized Jump Fix Message-ID: <20080717031721.GA24504@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 23:14:13 up 42 days, 7:55, 5 users, load average: 0.34, 0.73, 0.67 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2300 Lines: 61 Hi Ingo, This fix would apply to the ftrace tree which contains the jump-based immediate values. I don't know if this tree is still under active development, but I guess that it wouldn't hurt to fix it. Caused a kernel OOPS when loading the tracepoint probes once in a while on a 8-way x86_64. Immedate Values Optimized Jump Fix Fix the immediate values optimized jump fallback, which parameters were wrong following the last changes. It should be a 5 bytes instruction (not 2) with a 4 bytes operand. Signed-off-by: Mathieu Desnoyers --- arch/x86/kernel/immediate.c | 2 +- include/asm-x86/immediate.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) Index: linux-2.6-lttng/arch/x86/kernel/immediate.c =================================================================== --- linux-2.6-lttng.orig/arch/x86/kernel/immediate.c 2008-07-16 22:50:35.000000000 -0400 +++ linux-2.6-lttng/arch/x86/kernel/immediate.c 2008-07-16 22:51:07.000000000 -0400 @@ -500,7 +500,7 @@ __kprobes int arch_imv_update(struct __i "Jump target fallback at %lX, nr fail %d\n", imv->imv, ++nr_fail); #endif - imv->size = 1; + imv->size = 4; /* Fallback on movl */ } else { #ifdef DEBUG_IMMEDIATE static int nr_success; Index: linux-2.6-lttng/include/asm-x86/immediate.h =================================================================== --- linux-2.6-lttng.orig/include/asm-x86/immediate.h 2008-07-16 22:49:19.000000000 -0400 +++ linux-2.6-lttng/include/asm-x86/immediate.h 2008-07-16 22:51:07.000000000 -0400 @@ -132,7 +132,7 @@ struct __imv { BUILD_BUG_ON(sizeof(__typeof__(name##__imv)) > 1); \ asm (".section __imv,\"aw\",@progbits\n\t" \ _ASM_PTR "%c1, (3f)-4\n\t" \ - ".byte 0, 2\n\t" \ + ".byte 0, 5\n\t" \ ".previous\n\t" \ "mov $0,%0\n\t" \ "3:\n\t" \ -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/