From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Fri, 20 Jun 2014 17:40:04 +0000 Subject: re: tracing: Add help of snapshot feature when snapshot is empty Message-Id: <20140620174004.GA10971@mwanda> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernel-janitors@vger.kernel.org Hello Steven Rostedt (Red Hat), This is a semi-automatic email about new static checker warnings. The patch d8741e2e88ac: "tracing: Add help of snapshot feature when snapshot is empty" from Mar 5, 2013, leads to the following Smatch complaint: kernel/trace/trace.c:2933 s_show() error: we previously assumed 'iter->tr' could be null (see line 2927) kernel/trace/trace.c 2926 if (iter->ent = NULL) { 2927 if (iter->tr) { ^^^^^^^^ Existing check for "iter->tr". 2928 seq_printf(m, "# tracer: %s\n", iter->trace->name); 2929 seq_puts(m, "#\n"); 2930 test_ftrace_alive(m); 2931 } 2932 if (iter->snapshot && trace_empty(iter)) 2933 print_snapshot_help(m, iter); ^^^^^^^^^^^^^^^^^^^^^^^^^^^ "iter->tr" gets dereferenced inside the new call to print_snapshot_help(). 2934 else if (iter->trace && iter->trace->print_header) 2935 iter->trace->print_header(m); regards, dan carpenter