From patchwork Mon Feb 1 17:13:12 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnaldo Carvalho de Melo X-Patchwork-Id: 60943 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp159334lbb; Mon, 1 Feb 2016 09:13:51 -0800 (PST) X-Received: by 10.66.148.99 with SMTP id tr3mr39854516pab.19.1454346831273; Mon, 01 Feb 2016 09:13:51 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id v2si44477530pfi.243.2016.02.01.09.13.50; Mon, 01 Feb 2016 09:13:51 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753925AbcBARNX (ORCPT + 30 others); Mon, 1 Feb 2016 12:13:23 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:42455 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753128AbcBARNV (ORCPT ); Mon, 1 Feb 2016 12:13:21 -0500 Received: from [179.235.167.117] (helo=jouet.infradead.org) by bombadil.infradead.org with esmtpsa (Exim 4.80.1 #2 (Red Hat Linux)) id 1aQI2R-0005Pz-OY; Mon, 01 Feb 2016 17:13:19 +0000 Received: by jouet.infradead.org (Postfix, from userid 1000) id B7728143DFE; Mon, 1 Feb 2016 14:13:17 -0300 (BRT) From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Wang Nan , Adrian Hunter , Josh Poimboeuf , Arnaldo Carvalho de Melo Subject: [PATCH 2/2] perf tools: Fix fault in error patch of intel_pt_process_auxtrace_info() Date: Mon, 1 Feb 2016 14:13:12 -0300 Message-Id: <1454346792-24419-3-git-send-email-acme@kernel.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1454346792-24419-1-git-send-email-acme@kernel.org> References: <1454346792-24419-1-git-send-email-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wang Nan In error processing path of intel_pt_process_auxtrace_info() it calls thread__zput() to clean and free pt->unknown_thread which is created by thread__new(). However, when error raise, a segfault happen: # perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls 0 a anaconda-ks.cfg bin perf.data perf.data.old perf-f23-bringup.todo [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.217 MB perf.data ] # # perf script -F event,comm,pid,tid,time,addr,ip,sym,dso,iregs Samples for 'instructions:u' event do not have IREGS attribute set. Cannot print 'iregs' field. intel_pt_synth_events: failed to synthesize 'instructions' event type Segmentation fault (core dumped) # The problem is: there's a union in 'struct thread' combines a list_head and a rb_node. The standard life cycle of a thread is: init rb_node during creating, inserted into machine->threads rbtree uses rb_node, move to machine->dead_threads using list_head, clean by thread__put: list_del_init(&thread->node). In the above command, it clean a thread before adding it into list, causes the above segfault. This patch gives a fake list_head and link the thread into it before calling thread__zput(), get rid of the segfault. After this patch: # perf script -F event,comm,pid,tid,time,addr,ip,sym,dso,iregs Samples for 'instructions:u' event do not have IREGS attribute set. Cannot print 'iregs' field. intel_pt_synth_events: failed to synthesize 'instructions' event type 0x248 [0x88]: failed to process type: 70 # Reported-by: Tong Zhang Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Josh Poimboeuf Link: http://lkml.kernel.org/r/1454296865-19749-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/intel-pt.c | 4 ++++ 1 file changed, 4 insertions(+) -- 2.5.0 diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index 81a2eb77ba7f..e2add6376fec 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -2013,6 +2013,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event, struct auxtrace_info_event *auxtrace_info = &event->auxtrace_info; size_t min_sz = sizeof(u64) * INTEL_PT_PER_CPU_MMAPS; struct intel_pt *pt; + struct list_head dead_thread; int err; if (auxtrace_info->header.size < sizeof(struct auxtrace_info_event) + @@ -2153,6 +2154,9 @@ int intel_pt_process_auxtrace_info(union perf_event *event, return 0; err_delete_thread: + RB_CLEAR_NODE(&pt->unknown_thread->rb_node); + INIT_LIST_HEAD(&dead_thread); + list_add(&pt->unknown_thread->node, &dead_thread); thread__zput(pt->unknown_thread); err_free_queues: intel_pt_log_disable();