Commit 7fb0a5ee authored Apr 09, 2012 by Nikunj A. Dadhania Committed by Arnaldo Carvalho de Melo Apr 11, 2012

perf kvm: Finding struct machine fails for PERF_RECORD_MMAP



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.

The event->ip.pid field 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 <nikunj@linux.vnet.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120409081835.10576.22018.stgit@abhimanyu.in.ibm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 31d68e7b

tools/perf/util/session.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}

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