Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965024AbbHDOzC (ORCPT ); Tue, 4 Aug 2015 10:55:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:59202 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964912AbbHDOmJ (ORCPT ); Tue, 4 Aug 2015 10:42:09 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Steven Rostedt (Red Hat)" , Jiri Slaby Subject: [PATCH 3.12 088/123] tracing/filter: Do not WARN on operand count going below zero Date: Tue, 4 Aug 2015 16:40:32 +0200 Message-Id: <68387f89a0407ab2d1bf8060c7a56c15dcadd7ae.1438699154.git.jslaby@suse.cz> X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1924 Lines: 54 From: "Steven Rostedt (Red Hat)" 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- kernel/trace/trace_events_filter.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 7a0cf8dd9d95..c17533a3de71 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1349,7 +1349,9 @@ static int check_preds(struct filter_parse_state *ps) } 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) { -- 2.5.0 -- 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/