Re: [PATCH] perf tools: Fix printable strings in python3 scripts

[Arnaldo Carvalho de Melo]

Em Mon, Sep 28, 2020 at 10:11:35PM +0200, Jiri Olsa escreveu:
> Hagen reported broken strings in python3 tracepoint scripts:
> 
>   make PYTHON=python3
>   ./perf record -e sched:sched_switch -a -- sleep 5
>   ./perf script --gen-script py
>   ./perf script -s ./perf-script.py
> 
>   [..]
>   sched__sched_switch      7 563231.759525792        0 swapper   \
>   prev_comm=bytearray(b'swapper/7\x00\x00\x00\x00\x00\x00\x00'), \
>   prev_pid=0, prev_prio=120, prev_state=, next_comm=bytearray(b'mutex-thread-co\x00'),
> 
> The problem is in is_printable_array function that does not take
> zero byte into account and claim such string as not printable,
> so the code will create byte array instead of string.

Thanks, tested and applied.

- Arnaldo
 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 249de6e07458 ("perf script python: Fix string vs byte array resolving")
> Tested-by: Hagen Paul Pfeifer <hagen@xxxxxxxx>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/util/print_binary.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/print_binary.c b/tools/perf/util/print_binary.c
> index 599a1543871d..13fdc51c61d9 100644
> --- a/tools/perf/util/print_binary.c
> +++ b/tools/perf/util/print_binary.c
> @@ -50,7 +50,7 @@ int is_printable_array(char *p, unsigned int len)
>  
>  	len--;
>  
> -	for (i = 0; i < len; i++) {
> +	for (i = 0; i < len && p[i]; i++) {
>  		if (!isprint(p[i]) && !isspace(p[i]))
>  			return 0;
>  	}
> -- 
> 2.26.2
> 

-- 

- Arnaldo