From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761939AbXKTS1f (ORCPT ); Tue, 20 Nov 2007 13:27:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760932AbXKTS0B (ORCPT ); Tue, 20 Nov 2007 13:26:01 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:60134 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760903AbXKTS0A (ORCPT ); Tue, 20 Nov 2007 13:26:00 -0500 Date: Tue, 20 Nov 2007 10:23:18 -0800 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@kernel.org, torvalds@linux-foundation.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, phil.el@wanadoo.fr, safari-kernel@safari.iki.fi Subject: [patch 05/29] oProfile: oops when profile_pc() returns ~0LU Message-ID: <20071120182318.GF28611@kroah.com> References: <20071120181733.702234406@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="oprofile-oops-when-profile_pc-returns-0lu.patch" In-Reply-To: <20071120182248.GA28611@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 2.6.23-stable review patch. If anyone has any objections, please let us know. ------------------ From: Philippe Elie patch df9d177aa28d50e64bae6fbd6b263833079e3571 in mainline. Instruction pointer returned by profile_pc() can be a random value. This break the assumption than we can safely set struct op_sample.eip field to a magic value to signal to the per-cpu buffer reader side special event like task switch ending up in a segfault in get_task_mm() when profile_pc() return ~0UL. Fixed by sanitizing the sampled eip and reject/log invalid eip. Problem reported by Sami Farin, patch tested by him. Signed-off-by: Philippe Elie Tested-by: Sami Farin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/oprofile/cpu_buffer.c | 7 +++++++ drivers/oprofile/cpu_buffer.h | 1 + drivers/oprofile/oprofile_stats.c | 4 ++++ 3 files changed, 12 insertions(+) --- a/drivers/oprofile/cpu_buffer.c +++ b/drivers/oprofile/cpu_buffer.c @@ -64,6 +64,8 @@ int alloc_cpu_buffers(void) b->head_pos = 0; b->sample_received = 0; b->sample_lost_overflow = 0; + b->backtrace_aborted = 0; + b->sample_invalid_eip = 0; b->cpu = i; INIT_DELAYED_WORK(&b->work, wq_sync_buffer); } @@ -175,6 +177,11 @@ static int log_sample(struct oprofile_cp cpu_buf->sample_received++; + if (pc == ESCAPE_CODE) { + cpu_buf->sample_invalid_eip++; + return 0; + } + if (nr_available_slots(cpu_buf) < 3) { cpu_buf->sample_lost_overflow++; return 0; --- a/drivers/oprofile/cpu_buffer.h +++ b/drivers/oprofile/cpu_buffer.h @@ -42,6 +42,7 @@ struct oprofile_cpu_buffer { unsigned long sample_received; unsigned long sample_lost_overflow; unsigned long backtrace_aborted; + unsigned long sample_invalid_eip; int cpu; struct delayed_work work; } ____cacheline_aligned; --- a/drivers/oprofile/oprofile_stats.c +++ b/drivers/oprofile/oprofile_stats.c @@ -26,6 +26,8 @@ void oprofile_reset_stats(void) cpu_buf = &cpu_buffer[i]; cpu_buf->sample_received = 0; cpu_buf->sample_lost_overflow = 0; + cpu_buf->backtrace_aborted = 0; + cpu_buf->sample_invalid_eip = 0; } atomic_set(&oprofile_stats.sample_lost_no_mm, 0); @@ -61,6 +63,8 @@ void oprofile_create_stats_files(struct &cpu_buf->sample_lost_overflow); oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted", &cpu_buf->backtrace_aborted); + oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip", + &cpu_buf->sample_invalid_eip); } oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm", --