From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756024Ab2DIIWs (ORCPT ); Mon, 9 Apr 2012 04:22:48 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:39392 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754977Ab2DIIWr (ORCPT ); Mon, 9 Apr 2012 04:22:47 -0400 From: "Nikunj A. Dadhania" Subject: [BUG PATCH] perf: kvm - finding struct machine fails for PERF_RECORD_MMAP To: mingo@redhat.com, acme@ghostprotocols.net, dsahern@gmail.com Cc: a.p.zijlstra@chello.nl, paulus@samba.org, fweisbec@gmail.com, eranian@google.com, linux-kernel@vger.kernel.org, nikunj@linux.vnet.ibm.com Date: Mon, 09 Apr 2012 13:52:23 +0530 Message-ID: <20120409081835.10576.22018.stgit@abhimanyu.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit x-cbid: 12040908-5564-0000-0000-0000022166FD Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nikunj A. Dadhania Running 'perf kvm --host --guest --guestmount /tmp/guestmount record -a -g -- sleep 2' Was resulting in a segfault. For event type PERF_RECORD_MMAP, event->ip.pid is being used in perf_session__find_machine_for_cpumode, which is not correct. event->ip.pid happens to be 0 in this case and results in returning a NULL machine object. Finally, access to self->pid in machine__mmap_name, results in a segfault later. For PERF_RECORD_MMAP type, pass event->mmap.pid. Signed-off-by: Nikunj A. Dadhania --- tools/perf/util/session.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 9412e3b..00923cd 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -826,8 +826,16 @@ static struct machine * { const u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK; - if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) - return perf_session__find_machine(session, event->ip.pid); + if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) { + u32 pid; + + if (event->header.type == PERF_RECORD_MMAP) + pid = event->mmap.pid; + else + pid = event->ip.pid; + + return perf_session__find_machine(session, pid); + } return perf_session__find_host_machine(session); }