Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947667AbbGaV3u (ORCPT ); Fri, 31 Jul 2015 17:29:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46606 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753691AbbGaT6T (ORCPT ); Fri, 31 Jul 2015 15:58:19 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vince Weaver , Sasha Levin , Steven Rostedt Subject: [PATCH 4.1 182/267] tracing/filter: Do not WARN on operand count going below zero Date: Fri, 31 Jul 2015 12:40:33 -0700 Message-Id: <20150731194008.144544346@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150731194001.933895871@linuxfoundation.org> References: <20150731194001.933895871@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1825 Lines: 52 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (Red Hat)" commit b4875bbe7e68f139bd3383828ae8e994a0df6d28 upstream. When testing the fix for the trace filter, I could not come up with a scenario where the operand count goes below zero, so I added a WARN_ON_ONCE(cnt < 0) to the logic. But there is legitimate case that it can happen (although the filter would be wrong). # echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter That is, a single operation without any operands will hit the path where the WARN_ON_ONCE() can trigger. Although this is harmless, and the filter is reported as a error. But instead of spitting out a warning to the kernel dmesg, just fail nicely and report it via the proper channels. Link: http://lkml.kernel.org/r/558C6082.90608@oracle.com Reported-by: Vince Weaver Reported-by: Sasha Levin Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_filter.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1385,7 +1385,9 @@ static int check_preds(struct filter_par if (elt->op != OP_NOT) cnt--; n_normal_preds++; - WARN_ON_ONCE(cnt < 0); + /* all ops should have operands */ + if (cnt < 0) + break; } if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/