[tip:perf/core] perf record: Ensure return non-zero rc when mmap fail

tip-bot for Wang Nan
2016-03-05T08:17:38Z

Commit-ID: 95c365617aa37878592f2f1c6c64e1abb19f0d4a
Gitweb: http://git.kernel.org/tip/95c365617aa37878592f2f1c6c64e1abb19f0d4a
Author: Wang Nan <wangnan0@huawei.com>
AuthorDate: Fri, 26 Feb 2016 09:32:17 +0000
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 3 Mar 2016 11:10:36 -0300

perf record: Ensure return non-zero rc when mmap fail

perf_evlist__mmap_ex() can fail without setting errno (for example, fail
in condition checking. In this case all syscall is success).

If this happen, record__open() incorrectly returns 0. Force setting rc
is a quick way to avoid this problem, or we have to follow all possible
code path in perf_evlist__mmap_ex() to make sure there's at least one
system call before returning an error.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1456479154-136027-30-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 46e2772..515510e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -324,7 +324,10 @@ try_again:
} else {
pr_err("failed to mmap with %d (%s)\n", errno,
strerror_r(errno, msg, sizeof(msg)));
- rc = -errno;
+ if (errno)
+ rc = -errno;
+ else
+ rc = -EINVAL;
}
goto out;
}