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author | Jan Stancek <jstancek@redhat.com> | 2017-02-17 12:10:25 +0100 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2017-02-17 12:37:04 -0300 |
commit | 43db2843a4a41cc8cdb6ab696639aeee1f4d5062 (patch) | |
tree | e6b24505f0a6c455fa2e6026e77b2f7d3f84864c /tools/perf | |
parent | 92a7e1278005b6bb3459affc50b2b6e2464e7e7c (diff) | |
download | linux-stable-43db2843a4a41cc8cdb6ab696639aeee1f4d5062.tar.gz linux-stable-43db2843a4a41cc8cdb6ab696639aeee1f4d5062.tar.bz2 linux-stable-43db2843a4a41cc8cdb6ab696639aeee1f4d5062.zip |
perf header: Make build_cpu_topology skip offline/absent CPUs
When build_cpu_topo() encounters offline/absent CPUs, it fails to find any
sysfs entries and returns failure.
This leads to build_cpu_topology() and write_cpu_topology() failing as
well.
Because HEADER_CPU_TOPOLOGY has not been written, read leaves cpu_topology_map
NULL and we get NULL ptr deref at:
...
cmd_test
__cmd_test
test_and_print
run_test
test_session_topology
check_cpu_topology
36: Session topology :
--- start ---
test child forked, pid 14902
templ file: /tmp/perf-test-4CKocW
failed to write feature HEADER_CPU_TOPOLOGY
perf: Segmentation fault
Obtained 9 stack frames.
./perf(sighandler_dump_stack+0x41) [0x5095f1]
/lib64/libc.so.6(+0x35250) [0x7f4b7c3c9250]
./perf(test_session_topology+0x1db) [0x490ceb]
./perf() [0x475b68]
./perf(cmd_test+0x5b9) [0x4763c9]
./perf() [0x4945a3]
./perf(main+0x69f) [0x427e8f]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f4b7c3b5b35]
./perf() [0x427fb9]
test child interrupted
---- end ----
Session topology: FAILED!
This patch makes build_cpu_topology() skip offline/absent CPUs, by checking
their presence against cpu_map built from online CPUs.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/a271b770175524f4961d4903af33798358a4a518.1487146877.git.jstancek@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r-- | tools/perf/util/header.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 3d12c16e5103..1222f6c5e7b3 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -505,24 +505,31 @@ static void free_cpu_topo(struct cpu_topo *tp) static struct cpu_topo *build_cpu_topology(void) { - struct cpu_topo *tp; + struct cpu_topo *tp = NULL; void *addr; u32 nr, i; size_t sz; long ncpus; int ret = -1; + struct cpu_map *map; ncpus = sysconf(_SC_NPROCESSORS_CONF); if (ncpus < 0) return NULL; + /* build online CPU map */ + map = cpu_map__new(NULL); + if (map == NULL) { + pr_debug("failed to get system cpumap\n"); + return NULL; + } + nr = (u32)(ncpus & UINT_MAX); sz = nr * sizeof(char *); - addr = calloc(1, sizeof(*tp) + 2 * sz); if (!addr) - return NULL; + goto out_free; tp = addr; tp->cpu_nr = nr; @@ -532,10 +539,16 @@ static struct cpu_topo *build_cpu_topology(void) tp->thread_siblings = addr; for (i = 0; i < nr; i++) { + if (!cpu_map__has(map, i)) + continue; + ret = build_cpu_topo(tp, i); if (ret < 0) break; } + +out_free: + cpu_map__put(map); if (ret) { free_cpu_topo(tp); tp = NULL; |