From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756182Ab1CLW76 (ORCPT ); Sat, 12 Mar 2011 17:59:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:15477 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752381Ab1CLW7x (ORCPT ); Sat, 12 Mar 2011 17:59:53 -0500 From: Jiri Olsa To: rostedt@goodmis.org, fweisbec@gmail.com, mingo@redhat.com Cc: linux-kernel@vger.kernel.org, oleg@redhat.com, Jiri Olsa Subject: [PATCH 1/2] tracing - trace lost events properly Date: Sat, 12 Mar 2011 23:59:45 +0100 Message-Id: <1299970786-8075-2-git-send-email-jolsa@redhat.com> In-Reply-To: <1299970786-8075-1-git-send-email-jolsa@redhat.com> References: <1299970786-8075-1-git-send-email-jolsa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add proper handling of lost event trace, allowing callers to get correct trace buffer info. - returning TRACE_TYPE_PARTIAL_LINE, in case we dont fit into the trace_seq buffer - added WARN_ON to make sure we don't miss incorrect trace_seq handling wbr, jirka Signed-off-by: Jiri Olsa --- kernel/trace/trace.c | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9541c27..20d84f8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2013,9 +2013,10 @@ enum print_line_t print_trace_line(struct trace_iterator *iter) { enum print_line_t ret; - if (iter->lost_events) - trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", - iter->cpu, iter->lost_events); + if (iter->lost_events && + !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", + iter->cpu, iter->lost_events)) + return TRACE_TYPE_PARTIAL_LINE; if (iter->trace && iter->trace->print_line) { ret = iter->trace->print_line(iter); @@ -3229,6 +3230,13 @@ waitagain: if (iter->seq.len >= cnt) break; + + /* + * Setting the full flag means we reached the trace_seq buffer + * size and we should leave by partial output condition above. + * One of the trace_seq_* functions is not used properly. + */ + WARN_ON(iter->seq.full); } trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); -- 1.7.1