If feed perf a symbol filter in cmdline and the result is empty,
pressing 'Enter' in the hist browser causes crash:
# ./perf report perf.data <-- Common mistake for beginners
Then press 'Enter':
perf: Segmentation fault
-------- backtrace --------
/home/wangnan/perf[0x53e578]
/lib64/libc.so.6(+0x3545f)[0x7f76bafe045f]
/home/wangnan/perf[0x539dd4]
/home/wangnan/perf(perf_evlist__tui_browse_hists+0x96)[0x53d216]
/home/wangnan/perf(cmd_report+0x1b9f)[0x442c7f]
/home/wangnan/perf[0x47efa2]
/home/wangnan/perf(main+0x5f5)[0x432fa5]
/lib64/libc.so.6(__libc_start_main+0xf4)[0x7f76bafccbd4]
/home/wangnan/perf[0x4330d4]
This is because 'perf.data' is interpreted as a symbol filter, and the
result is empty, so selection is empty. However,
hist_browser__toggle_fold() forgets to check it.
This patch simply return false when selection is NULL.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1449455746-41952-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
4938cf0c7a