+++ /dev/null
-From foo@baz Tue Sep 11 12:05:55 CEST 2018
-From: Jiri Olsa <jolsa@kernel.org>
-Date: Fri, 17 Aug 2018 13:45:56 +0200
-Subject: perf python: Fix pyrf_evlist__read_on_cpu() interface
-
-From: Jiri Olsa <jolsa@kernel.org>
-
-[ Upstream commit 721f0dfc3ce821c6a32820ab63edfb48ed4af075 ]
-
-Jaroslav reported errors from valgrind over perf python script:
-
- # echo 0 > /sys/devices/system/cpu/cpu4/online
- # valgrind ./test.py
- ==7524== Memcheck, a memory error detector
- ...
- ==7524== Command: ./test.py
- ==7524==
- pid 7526 exited
- ==7524== Invalid read of size 8
- ==7524== at 0xCC2C2B3: perf_mmap__read_forward (evlist.c:780)
- ==7524== by 0xCC2A681: pyrf_evlist__read_on_cpu (python.c:959)
- ...
- ==7524== Address 0x65c4868 is 16 bytes after a block of size 459,36..
- ==7524== at 0x4C2B955: calloc (vg_replace_malloc.c:711)
- ==7524== by 0xCC2F484: zalloc (util.h:35)
- ==7524== by 0xCC2F484: perf_evlist__alloc_mmap (evlist.c:978)
- ...
-
-The reason for this is in the python interface, that allows a script to
-pass arbitrary cpu number, which is then used to access struct
-perf_evlist::mmap array. That's obviously wrong and works only when if
-all cpus are available and fails if some cpu is missing, like in the
-example above.
-
-This patch makes pyrf_evlist__read_on_cpu() search the evlist's maps
-array for the proper map to access.
-
-It's linear search at the moment. Based on the way how is the
-read_on_cpu used, I don't think we need to be fast in here. But we
-could add some hash in the middle to make it fast/er.
-
-We don't allow python interface to set write_backward event attribute,
-so it's safe to check only evlist's mmaps.
-
-Reported-by: Jaroslav Škarvada <jskarvad@redhat.com>
-Signed-off-by: Jiri Olsa <jolsa@kernel.org>
-Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
-Cc: David Ahern <dsahern@gmail.com>
-Cc: Joe Mario <jmario@redhat.com>
-Cc: Namhyung Kim <namhyung@kernel.org>
-Cc: Peter Zijlstra <peterz@infradead.org>
-Link: http://lkml.kernel.org/r/20180817114556.28000-3-jolsa@kernel.org
-Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- tools/perf/util/python.c | 20 +++++++++++++++++++-
- 1 file changed, 19 insertions(+), 1 deletion(-)
-
---- a/tools/perf/util/python.c
-+++ b/tools/perf/util/python.c
-@@ -11,6 +11,7 @@
- #include "cpumap.h"
- #include "print_binary.h"
- #include "thread_map.h"
-+#include "mmap.h"
-
- #if PY_MAJOR_VERSION < 3
- #define _PyUnicode_FromString(arg) \
-@@ -976,6 +977,20 @@ static PyObject *pyrf_evlist__add(struct
- return Py_BuildValue("i", evlist->nr_entries);
- }
-
-+static struct perf_mmap *get_md(struct perf_evlist *evlist, int cpu)
-+{
-+ int i;
-+
-+ for (i = 0; i < evlist->nr_mmaps; i++) {
-+ struct perf_mmap *md = &evlist->mmap[i];
-+
-+ if (md->cpu == cpu)
-+ return md;
-+ }
-+
-+ return NULL;
-+}
-+
- static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
- PyObject *args, PyObject *kwargs)
- {
-@@ -990,7 +1005,10 @@ static PyObject *pyrf_evlist__read_on_cp
- &cpu, &sample_id_all))
- return NULL;
-
-- md = &evlist->mmap[cpu];
-+ md = get_md(evlist, cpu);
-+ if (!md)
-+ return NULL;
-+
- if (perf_mmap__read_init(md) < 0)
- goto end;
-