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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nageswara R Sastry <nasastry@in.ibm.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 022/187] perf c2c: Fix c2c report for empty numa node
Date:   Thu,  4 Apr 2019 10:45:59 +0200
Message-Id: <20190404084604.128426074@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit e34c940245437f36d2c492edd1f8237eff391064 ]

Ravi Bangoria reported that we fail with an empty NUMA node with the
following message:

  $ lscpu
  NUMA node0 CPU(s):
  NUMA node1 CPU(s):   0-4

  $ sudo ./perf c2c report
  node/cpu topology bugFailed setup nodes

Fix this by detecting the empty node and keeping its CPU set empty.

Reported-by: Nageswara R Sastry <nasastry@in.ibm.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190305152536.21035-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/builtin-c2c.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index f3aa9d02a5ab..763c2edf52e7 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2055,6 +2055,12 @@ static int setup_nodes(struct perf_session *session)
 		if (!set)
 			return -ENOMEM;
 
+		nodes[node] = set;
+
+		/* empty node, skip */
+		if (cpu_map__empty(map))
+			continue;
+
 		for (cpu = 0; cpu < map->nr; cpu++) {
 			set_bit(map->map[cpu], set);
 
@@ -2063,8 +2069,6 @@ static int setup_nodes(struct perf_session *session)
 
 			cpu2node[map->map[cpu]] = node;
 		}
-
-		nodes[node] = set;
 	}
 
 	setup_nodes_header();
-- 
2.19.1