[PATCH 59/83] perf test shell: Fix test case probe libc's inet_pton on s390x

From: Arnaldo Carvalho de Melo
Date: Fri Nov 17 2017 - 15:20:18 EST

From: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>

The 'perf test' case "probe libc's inet_pton & backtrace it with ping"
fails on s390x. The reason is the 'realpath /lib64/ld*.so.* | uniq' line
which returns 2 libraries:

root@s35lp76 shell]# realpath /lib64/ld*.so.* | uniq
[root@s35lp76 shell]

This output makes the "perf probe" command lines invalid.

Use ldd tool to find out the libraries required by "bash" and check if
symbol "inet_pton" is part of the "libc" library. Some distros do not
have a /lib64 directory.

I have also added a check for the existence of an IPv6 network interface
before it is being used.

Committer changes:

We can't really use ldd for libc, as in some systems, such as x86_64, it
has hardlinks and then ldd sees one and the kernel the other, so grep
for libc in /proc/self/maps to get the one we'll receive from

Thomas checked this change and acked it.

Signed-off-by: Thomas-Mich Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Suggested-by: Hendrik BrÃckner <brueckner@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Hendrik BrÃckner <brueckner@xxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171114133409.GN8836@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/tests/shell/trace+probe_libc_inet_pton.sh | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/shell/trace+probe_libc_inet_pton.sh b/tools/perf/tests/shell/trace+probe_libc_inet_pton.sh
index 7a84d73324e3..8b3da21a08f1 100755
--- a/tools/perf/tests/shell/trace+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/trace+probe_libc_inet_pton.sh
@@ -10,8 +10,8 @@

. $(dirname $0)/lib/probe.sh

-ld=$(realpath /lib64/ld*.so.* | uniq)
-libc=$(echo $ld | sed 's/ld/libc/g')
+libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
+nm -g $libc 2>/dev/null | fgrep -q inet_pton || exit 254

trace_libc_inet_pton_backtrace() {
@@ -37,6 +37,9 @@ trace_libc_inet_pton_backtrace() {

+# Check for IPv6 interface existence
+ip a sh lo | fgrep -q inet6 || exit 2
skip_if_no_perf_probe && \
perf probe -q $libc inet_pton && \