Sometimes when adding a kprobe by perf, it results in multiple probe
points, such as the following:
# ./perf probe -l
probe:vfs_getname (on getname_flags:73@fs/namei.c with pathname)
probe:vfs_getname_1 (on getname_flags:73@fs/namei.c with pathname)
probe:vfs_getname_2 (on getname_flags:73@fs/namei.c with pathname)
# cat /sys/kernel/debug/tracing/kprobe_events
p:probe/vfs_getname _text+5501804 pathname=+0(+0(%gpr31)):string
p:probe/vfs_getname_1 _text+5505388 pathname=+0(+0(%gpr31)):string
p:probe/vfs_getname_2 _text+5508396 pathname=+0(+0(%gpr31)):string
In this test, we need to record all of them and expect any of them in
the perf-script output, since it's not clear which one will be used for
the desired syscall:
# perf stat -e probe:vfs_getname\* -- touch /tmp/nic
Performance counter stats for 'touch /tmp/nic':
31 probe:vfs_getname_2
0 probe:vfs_getname_1
1 probe:vfs_getname
0.
001421826 seconds time elapsed
0.
001506000 seconds user
0.
000000000 seconds sys
If the test relies only on probe:vfs_getname, it might easily miss the
relevant data.
Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
LPU-Reference:
20200722135845.29958-1-mpetlan@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
record_open_file() {
echo "Recording open file:"
- perf record -o ${perfdata} -e probe:vfs_getname touch $file
+ perf record -o ${perfdata} -e probe:vfs_getname\* touch $file
}
perf_script_filenames() {
echo "Looking at perf.data file for vfs_getname records for the file we touched:"
perf script -i ${perfdata} | \
- egrep " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:vfs_getname: +\([[:xdigit:]]+\) +pathname=\"${file}\""
+ egrep " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:vfs_getname[_0-9]*: +\([[:xdigit:]]+\) +pathname=\"${file}\""
}
add_probe_vfs_getname || skip_if_no_debuginfo