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Subject[PATCH 11/30] perf test shell: Fix test case probe libc's inet_pton on s390x
Date
From: Thomas Richter <tmricht@linux.vnet.ibm.com>

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
/usr/lib64/ld-2.26.so
/usr/lib64/ld_pre_smc.so.1.0.1
[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
PERF_RECORD_MMAP.

Thomas checked this change and acked it.

Signed-off-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Suggested-by: Hendrik Brückner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brückner <brueckner@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20171114133409.GN8836@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
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() {
idx=0
@@ -37,6 +37,9 @@ trace_libc_inet_pton_backtrace() {
done
}

+# 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 && \
trace_libc_inet_pton_backtrace
--
2.13.6
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