From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753006AbYLQVfF (ORCPT ); Wed, 17 Dec 2008 16:35:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751494AbYLQVev (ORCPT ); Wed, 17 Dec 2008 16:34:51 -0500 Received: from www.tglx.de ([62.245.132.106]:54619 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751154AbYLQVeu (ORCPT ); Wed, 17 Dec 2008 16:34:50 -0500 Date: Wed, 17 Dec 2008 22:34:13 +0100 (CET) From: Thomas Gleixner To: LKML cc: Steven Rostedt , Ingo Molnar Subject: trace: fix task state printout Message-ID: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Impact: tracer task state decoding is wrong, size check is buggy The tracing code has interesting varieties of printing out task state. Unfortunalely only one of the instances is correct as it copies the code from sched.c:sched_show_task(). The others are plain wrong as they treatthe bitfield as an integer offset into the character array. Also the size check of the character array is wrong as it includes the trailing \0. Use a common state decoder inline which does the Right Thing. Signed-off-by: Thomas Gleixner --- kernel/trace/trace.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) Index: linux-2.6/kernel/trace/trace.c =================================================================== --- linux-2.6.orig/kernel/trace/trace.c +++ linux-2.6/kernel/trace/trace.c @@ -1301,6 +1301,13 @@ lat_print_timestamp(struct trace_seq *s, static const char state_to_char[] = TASK_STATE_TO_CHAR_STR; +static int task_state_char(unsigned long state) +{ + int bit = state ? __ffs(state) + 1 : 0; + + return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?'; +} + /* * The message is supposed to contain an ending newline. * If the printing stops prematurely, try to add a newline of our own. @@ -1395,12 +1402,8 @@ print_lat_fmt(struct trace_iterator *ite trace_assign_type(field, entry); - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - - state = field->prev_state ? - __ffs(field->prev_state) + 1 : 0; - S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X'; + T = task_state_char(field->next_state); + S = task_state_char(field->prev_state); comm = trace_find_cmdline(field->next_pid); trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n", field->prev_pid, @@ -1518,10 +1521,8 @@ static enum print_line_t print_trace_fmt trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; + T = task_state_char(field->next_state); + S = task_state_char(field->prev_state); ret = trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c\n", field->prev_pid, field->prev_prio, @@ -1620,12 +1621,9 @@ static enum print_line_t print_raw_fmt(s trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - if (entry->type == TRACE_WAKE) - S = '+'; + T = task_state_char(field->next_state); + S = entry->type == TRACE_WAKE ? '+' : + task_state_char(field->prev_state); ret = trace_seq_printf(s, "%d %d %c %d %d %d %c\n", field->prev_pid, field->prev_prio, @@ -1711,12 +1709,9 @@ static enum print_line_t print_hex_fmt(s trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - if (entry->type == TRACE_WAKE) - S = '+'; + T = task_state_char(field->next_state); + S = entry->type == TRACE_WAKE ? '+' : + task_state_char(field->prev_state); SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid); SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio); SEQ_PUT_HEX_FIELD_RET(s, S);