From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752975AbZEaFv4 (ORCPT ); Sun, 31 May 2009 01:51:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751977AbZEaFvs (ORCPT ); Sun, 31 May 2009 01:51:48 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:52348 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751573AbZEaFvs (ORCPT ); Sun, 31 May 2009 01:51:48 -0400 Message-ID: <4A221B41.4030907@cn.fujitsu.com> Date: Sun, 31 May 2009 13:53:05 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Frederic Weisbecker , Steven Rostedt CC: Ingo Molnar , LKML Subject: [PATCH] tracing/filters: use strcmp() instead of strncmp() Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Trace filter is not working normally: # echo 'name == et' > tracing/events/irq/irq_handler_entry/filter # echo 1 > tracing/events/irq/irq_handler_entry/enable # cat trace_pipe -0 [001] 1363.423175: irq_handler_entry: irq=18 handler=eth0 -0 [001] 1363.934528: irq_handler_entry: irq=18 handler=eth0 It's because we pass to trace_define_field() the information of __str_loc_##item, but not the actual string, so pred->str_len == field->size == sizeof(unsigned short), thus it always compare at most 2 bytes when filtering on __string() field. Since __string() is dynamic size, we are not able to set field->size to string length. Alternatively this patch uses strcmp() instead of strncmp(), for both static strings and dynamic strings. strncmp() is not necessary, since strings passed to it are already guaranteed to be NULL-terminated. [ Impact: make filter facility working normally for dynamic strings ] Signed-off-by: Li Zefan --- kernel/trace/trace.h | 1 - kernel/trace/trace_events_filter.c | 7 ++----- 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6e735d4..ec8970b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -758,7 +758,6 @@ struct filter_pred { filter_pred_fn_t fn; u64 val; char str_val[MAX_FILTER_STR_VAL]; - int str_len; char *field_name; int offset; int not; diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index a854eed..8362586 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -158,7 +158,7 @@ static int filter_pred_string(struct filter_pred *pred, void *event, char *addr = (char *)(event + pred->offset); int cmp, match; - cmp = strncmp(addr, pred->str_val, pred->str_len); + cmp = strcmp(addr, pred->str_val); match = (!cmp) ^ pred->not; @@ -182,7 +182,7 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event, char *addr = (char *)(event + str_loc); int cmp, match; - cmp = strncmp(addr, pred->str_val, pred->str_len); + cmp = strcmp(addr, pred->str_val); match = (!cmp) ^ pred->not; @@ -341,7 +341,6 @@ static void filter_clear_pred(struct filter_pred *pred) { kfree(pred->field_name); pred->field_name = NULL; - pred->str_len = 0; } static int filter_set_pred(struct filter_pred *dest, @@ -576,7 +575,6 @@ static int filter_add_pred(struct filter_parse_state *ps, fn = filter_pred_string; else fn = filter_pred_strloc; - pred->str_len = field->size; if (pred->op == OP_NE) pred->not = 1; return filter_add_pred_fn(ps, call, pred, fn); @@ -957,7 +955,6 @@ static struct filter_pred *create_pred(int op, char *operand1, char *operand2) } strcpy(pred->str_val, operand2); - pred->str_len = strlen(operand2); pred->op = op; -- 1.5.4.rc3