From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163122AbdDUVnD (ORCPT ); Fri, 21 Apr 2017 17:43:03 -0400 Received: from mail.kernel.org ([198.145.29.136]:50818 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1042386AbdDUVde (ORCPT ); Fri, 21 Apr 2017 17:33:34 -0400 Message-Id: <20170421213328.134222116@goodmis.org> User-Agent: quilt/0.63-1 Date: Fri, 21 Apr 2017 17:30:22 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton Subject: [for-next][PATCH 02/33] ftrace: Fix indexing of t_hash_start() from t_next() References: <20170421213020.875637678@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0002-ftrace-Fix-indexing-of-t_hash_start-from-t_next.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" t_hash_start() does not increment *pos, where as t_next() must. But when t_next() does increment *pos, it must still pass in the original *pos to t_hash_start() otherwise it will skip the first instance: # cd /sys/kernel/debug/tracing # echo schedule:traceoff > set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter # echo call_rcu > set_ftrace_filter # cat set_ftrace_filter call_rcu schedule:traceoff:unlimited do_IRQ:traceoff:unlimited The above called t_hash_start() from t_start() as there was only one function (call_rcu), but if we add another function: # echo xfrm_policy_destroy_rcu >> set_ftrace_filter # cat set_ftrace_filter call_rcu xfrm_policy_destroy_rcu do_IRQ:traceoff:unlimited The "schedule:traceoff" disappears. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4b6459a57fbc..b21a3e61ac74 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3205,6 +3205,7 @@ static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; + loff_t l = *pos; /* t_hash_start() must use original pos */ void *ret; if (unlikely(ftrace_disabled)) @@ -3216,13 +3217,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos) if (iter->flags & FTRACE_ITER_PRINTALL) { /* next must increment pos, and t_hash_start does not */ (*pos)++; - return t_hash_start(m, pos); + return t_hash_start(m, &l); } ret = t_func_next(m, pos); if (!ret) - return t_hash_start(m, pos); + return t_hash_start(m, &l); return ret; } -- 2.10.2