From b963c1d6261eb7fba1ba14074fb447521be84add Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 3 Jan 2023 10:21:01 -0300 Subject: perf test record_probe_libc_inet_pton: Fix failure due to extra inet_pton() backtrace in glibc >= 2.35 Starting with glibc 2.35 there are extra inet_pton() calls when doing a IPv6 ping as in one of the 'perf test' entry, which makes it fail: # perf test inet_pton 89: probe libc's inet_pton & backtrace it with ping : FAILED! # If we look at what this script is expecting (commenting out the removal of the temporary files in it): # cat /tmp/expected.aT6 ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\) .*inet_pton\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6|inlined\)$ getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6\)$ .*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$ # And looking at what we are getting out of 'perf script', to match with the above: # cat /tmp/perf.script.IUC ping 623883 [006] 265438.471610: probe_libc:inet_pton: (7f32bcf314c0) 1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6) 29510 __libc_start_call_main+0x80 (/usr/lib64/libc.so.6) ping 623883 [006] 265438.471664: probe_libc:inet_pton: (7f32bcf314c0) 1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6) fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6) 491e [unknown] (/usr/bin/ping) # We see that its just the first call to inet_pton() that didn't came thru getaddrinfo(), so if we ignore the first the script matches what it expects, testing that using 'perf probe' + 'perf record' + 'perf script' with callchains on userspace targets is producing the expected results. Since we don't have a 'perf script --skip' to help us here, use tac + grep to do that, resulting in a one liner that makes this script work on both older glibc versions as well as with 2.35. With it, on fedora 36, x86, glibc 2.35: # perf test inet_pton 90: probe libc's inet_pton & backtrace it with ping : Ok # perf test -v inet_pton 90: probe libc's inet_pton & backtrace it with ping : --- start --- test child forked, pid 627197 ping 627220 1 267956.962402: probe_libc:inet_pton_1: (7f488bf314c0) 1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6) fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6) 491e n (/usr/bin/ping) test child finished with 0 ---- end ---- probe libc's inet_pton & backtrace it with ping: Ok # And on Ubuntu 22.04.1 LTS on a Libre Computer ROC-RK3399-PC arm64 system: Before this patch it works (see that the script used has no 'tac' to remove the first event): root@roc-rk3399-pc:~# dpkg -l | grep libc-bin ii libc-bin 2.35-0ubuntu3.1 arm64 GNU C Library: Binaries root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh root@roc-rk3399-pc:~# perf test inet_pton 86: probe libc's inet_pton & backtrace it with ping : Ok root@roc-rk3399-pc:~# perf test -v inet_pton 86: probe libc's inet_pton & backtrace it with ping : --- start --- test child forked, pid 1375 ping 1399 [000] 4114.417450: probe_libc:inet_pton: (ffffb3e26120) 106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6) d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6) 2b68 [unknown] (/usr/bin/ping) test child finished with 0 ---- end ---- probe libc's inet_pton & backtrace it with ping: Ok root@roc-rk3399-pc:~# And after it continues to work: root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac > $perf_script root@roc-rk3399-pc:~# perf test inet_pton 86: probe libc's inet_pton & backtrace it with ping : Ok root@roc-rk3399-pc:~# perf test -v inet_pton 86: probe libc's inet_pton & backtrace it with ping : --- start --- test child forked, pid 6995 ping 7019 [005] 4832.160741: probe_libc:inet_pton: (ffffa62e6120) 106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6) d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6) 2b68 [unknown] (/usr/bin/ping) test child finished with 0 ---- end ---- probe libc's inet_pton & backtrace it with ping: Ok root@roc-rk3399-pc:~# Reported-by: Thomas Richter Cc: Adrian Hunter Cc: Heiko Carstens Cc: Ian Rogers Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Sumanth Korikkar Cc: Sven Schnelle Cc: Vasily Gorbik Link: http://lore.kernel.org/lkml/Y7QyPkPlDYip3cZH@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/tests/shell/record+probe_libc_inet_pton.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/perf') diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh index 34c400ccbe04..216b6b64caa3 100755 --- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh +++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh @@ -57,7 +57,7 @@ trace_libc_inet_pton_backtrace() { perf_data=`mktemp -u /tmp/perf.data.XXX` perf_script=`mktemp -u /tmp/perf.script.XXX` perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1 - perf script -i $perf_data > $perf_script + perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac > $perf_script exec 3<$perf_script exec 4<$expected -- cgit v1.2.3