From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933369AbdKGAIX (ORCPT ); Mon, 6 Nov 2017 19:08:23 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52568 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932775AbdKFXya (ORCPT ); Mon, 6 Nov 2017 18:54:30 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Chunyu Hu" , "Steven Rostedt (VMware)" Date: Mon, 06 Nov 2017 23:03:02 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 135/294] tracing: Fix freeing of filter in create_filter() when set_str is false In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (VMware)" commit 8b0db1a5bdfcee0dbfa89607672598ae203c9045 upstream. Performing the following task with kmemleak enabled: # cd /sys/kernel/tracing/events/irq/irq_handler_entry/ # echo 'enable_event:kmem:kmalloc:3 if irq >' > trigger # echo 'enable_event:kmem:kmalloc:3 if irq > 31' > trigger # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8800b9290308 (size 32): comm "bash", pid 1114, jiffies 4294848451 (age 141.139s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] kmem_cache_alloc_trace+0x158/0x290 [] create_filter_start.constprop.28+0x99/0x940 [] create_filter+0xa9/0x160 [] create_event_filter+0xc/0x10 [] set_trigger_filter+0xe5/0x210 [] event_enable_trigger_func+0x324/0x490 [] event_trigger_write+0x1a2/0x260 [] __vfs_write+0xd7/0x380 [] vfs_write+0x101/0x260 [] SyS_write+0xab/0x130 [] entry_SYSCALL_64_fastpath+0x1f/0xbe [] 0xffffffffffffffff The function create_filter() is passed a 'filterp' pointer that gets allocated, and if "set_str" is true, it is up to the caller to free it, even on error. The problem is that the pointer is not freed by create_filter() when set_str is false. This is a bug, and it is not up to the caller to free the filter on error if it doesn't care about the string. Link: http://lkml.kernel.org/r/1502705898-27571-2-git-send-email-chuhu@redhat.com Fixes: 38b78eb85 ("tracing: Factorize filter creation") Reported-by: Chunyu Hu Tested-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Ben Hutchings --- kernel/trace/trace_events_filter.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1950,6 +1950,10 @@ static int create_filter(struct ftrace_e if (err && set_str) append_filter_err(ps, filter); } + if (err && !set_str) { + free_event_filter(filter); + filter = NULL; + } create_filter_finish(ps); *filterp = filter;