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authorArnaldo Carvalho de Melo <acme@redhat.com>2017-11-13 16:06:29 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-11-28 14:21:01 -0300
commit4a2233b194c77ae1ea8304cb7c00b551de4313f0 (patch)
tree4f9940561f9fea24c14c34ab3d410580b4d299ff /tools/perf
parent501e5bbec3c19498fa520fd3ffd68bd907f31bf7 (diff)
downloadlinux-4a2233b194c77ae1ea8304cb7c00b551de4313f0.tar.bz2
perf machine: Guard against NULL in machine__exit()
A recent fix for 'perf trace' introduced a bug where machine__exit(trace->host) could be called while trace->host was still NULL, so make this more robust by guarding against NULL, just like free() does. The problem happens, for instance, when !root users try to run 'perf trace': [acme@jouet linux]$ trace Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit) Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' perf: Segmentation fault Obtained 7 stack frames. [0x4f1b2e] /lib64/libc.so.6(+0x3671f) [0x7f43a1dd971f] [0x4f3fec] [0x47468b] [0x42a2db] /lib64/libc.so.6(__libc_start_main+0xe9) [0x7f43a1dc3509] [0x42a6c9] Segmentation fault (core dumped) [acme@jouet linux]$ Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrei Vagin <avagin@openvz.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vasily Averin <vvs@virtuozzo.com> Cc: Wang Nan <wangnan0@huawei.com> Fixes: 33974a414ce2 ("perf trace: Call machine__exit() at exit") Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/machine.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 6a8d03c3d9b7..270f3223c6df 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -172,6 +172,9 @@ void machine__exit(struct machine *machine)
{
int i;
+ if (machine == NULL)
+ return;
+
machine__destroy_kernel_maps(machine);
map_groups__exit(&machine->kmaps);
dsos__exit(&machine->dsos);