Re: [PATCH v8 2/3] perf tests: avoid storing an absolute path in perf binary

[Arnaldo Carvalho de Melo]

Em Mon, May 24, 2021 at 04:15:13AM -0700, Denys Zagorui escreveu:
> python binding test uses PYTHONPATH definition to find python/perf.so
> library. This definition is an absolute path that makes perf binary
> unreproducible. This path can be found during runtime execution.
> 
> Signed-off-by: Denys Zagorui <dzagorui@xxxxxxxxx>
> ---
>  tools/perf/tests/Build        |  2 +-
>  tools/perf/tests/python-use.c | 25 ++++++++++++++++++++++---
>  2 files changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
> index 650aec19d490..a20098dcdbc4 100644
> --- a/tools/perf/tests/Build
> +++ b/tools/perf/tests/Build
> @@ -98,5 +98,5 @@ perf-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
>  endif
>  
>  CFLAGS_attr.o         += -DBINDIR="BUILD_STR($(bindir_SQ))" -DPYTHON="BUILD_STR($(PYTHON_WORD))"
> -CFLAGS_python-use.o   += -DPYTHONPATH="BUILD_STR($(OUTPUT)python)" -DPYTHON="BUILD_STR($(PYTHON_WORD))"
> +CFLAGS_python-use.o   += -DPYTHON="BUILD_STR($(PYTHON_WORD))"
>  CFLAGS_dwarf-unwind.o += -fno-optimize-sibling-calls
> diff --git a/tools/perf/tests/python-use.c b/tools/perf/tests/python-use.c
> index 98c6d474aa6f..32af71300aa3 100644
> --- a/tools/perf/tests/python-use.c
> +++ b/tools/perf/tests/python-use.c
> @@ -8,18 +8,37 @@
>  #include <linux/compiler.h>
>  #include "tests.h"
>  #include "util/debug.h"
> +#include "util/util.h"
> +#include <sys/stat.h>
> +#include <limits.h>
> +#include <libgen.h>
>  
>  int test__python_use(struct test *test __maybe_unused, int subtest __maybe_unused)
>  {
>  	char *cmd;
> -	int ret;
> +	int ret = -1;
> +	char *exec_path;
> +	char buf[PATH_MAX];
> +	char *pythonpath;
> +	struct stat sb;
> +
> +	perf_exe(buf, PATH_MAX);
> +	exec_path = dirname(buf);
> +
> +	if (asprintf(&pythonpath, "%s/python", exec_path) < 0)
> +		return ret;
> +
> +	if (stat(pythonpath, &sb) || !S_ISDIR(sb.st_mode))
> +		pythonpath[0] = 0;
>  
>  	if (asprintf(&cmd, "echo \"import sys ; sys.path.append('%s'); import perf\" | %s %s",
> -		     PYTHONPATH, PYTHON, verbose > 0 ? "" : "2> /dev/null") < 0)
> -		return -1;
> +		     pythonpath, PYTHON, verbose > 0 ? "" : "2> /dev/null") < 0)
> +		goto out;
>  
>  	pr_debug("python usage test: \"%s\"\n", cmd);
>  	ret = system(cmd) ? -1 : 0;
>  	free(cmd);
> +out:
> +	free(pythonpath);
>  	return ret;
>  }
> -- 
> 2.26.2.Cisco
> 

I noticed this is failing the test, nothing is being appended. I'll
investigate later. Can you try to reproduce this? I build perf with:

alias m='perf stat -e cycles:u,instructions:u make -k CORESIGHT=1 BUILD_BPF_SKEL=1 PYTHON=python3 O=/tmp/build/perf -C tools/perf install-bin && perf test python'


⬢[acme@toolbox perf]$ perf test python
19: 'import perf' in python                                         : FAILED!
⬢[acme@toolbox perf]$ perf test -v python
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
19: 'import perf' in python                                         :
--- start ---
test child forked, pid 347155
python usage test: "echo "import sys ; sys.path.append(''); import perf" | '/usr/bin/python3' "
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'perf'
test child finished with -1
---- end ----
'import perf' in python: FAILED!
⬢[acme@toolbox perf]$ git log --oneline -3
60cdbfd0586e53c3 (HEAD) perf tests: Avoid storing an absolute path in perf binary
f7fc0d1c915a74ff perf inject: Do not inject BUILD_ID record if MMAP2 has it
0c3f7b38d72b9247 perf inject: Call dso__put() even if dso->hit is set
⬢[acme@toolbox perf]$