RE: [PATCH 1/2] perf probe: Only call probe_file__get_events() when fd is valid

[平松雅巳 / HIRAMATU，MASAMI]

From: Arnaldo Carvalho de Melo [mailto:acme@xxxxxxxxxx]
>Em Thu, Nov 05, 2015 at 01:19:24PM +0000, Wang Nan escreveu:
>> In system with kprobe enabled but uprobe turned off, 'perf probe -d'
>> causes segfault because it calls probe_file__get_events() with a
>> negative fd (when deleting uprobe events).
>>
>> This patch validates fds before calling probe_file__get_events().
>
>Wouldn't this shorter patch be more robust by deferring the validation
>to just before using the 'fd' value?
>
>The end result is that probe_file__get_events() will return -ENOENT in
>both calls, so ret and ret2 will both be set to -ENOENT, as in your
>patch.
>
>Masami?

Yes, I've suggested so :)
https://lkml.org/lkml/2015/11/5/353

Thanks!



>
>- Arnaldo
>
>diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
>index 89dbeb92c68e..f04a8318a1a7 100644
>--- a/tools/perf/util/probe-file.c
>+++ b/tools/perf/util/probe-file.c
>@@ -138,6 +138,9 @@ struct strlist *probe_file__get_rawlist(int fd)
> 	char *p;
> 	struct strlist *sl;
>
>+	if (fd < 0)
>+		return NULL;
>+
> 	sl = strlist__new(NULL, NULL);
>
> 	fp = fdopen(dup(fd), "r");
>
>
>diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
>index 89dbeb92c68e..e5dc8e62f0f1 100644
>--- a/tools/perf/util/probe-file.c
>+++ b/tools/perf/util/probe-file.c
>@@ -169,6 +169,9 @@ static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
> 	struct probe_trace_event tev;
> 	int ret = 0;
>
>+	if (fd < 0)
>+		return NULL;
>+
> 	memset(&tev, 0, sizeof(tev));
> 	rawlist = probe_file__get_rawlist(fd);
> 	if (!rawlist)
>
>
>> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
>> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
>> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
>> ---
>>  tools/perf/builtin-probe.c | 12 ++++++++++--
>>  1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
>> index 132afc9..861aa89 100644
>> --- a/tools/perf/builtin-probe.c
>> +++ b/tools/perf/builtin-probe.c
>> @@ -384,7 +384,11 @@ static int perf_del_probe_events(struct strfilter *filter)
>>  		goto out;
>>  	}
>>
>> -	ret = probe_file__get_events(kfd, filter, klist);
>> +	if (kfd < 0)
>> +		ret = -ENOENT;
>> +	else
>> +		ret = probe_file__get_events(kfd, filter, klist);
>> +
>>  	if (ret == 0) {
>>  		strlist__for_each(ent, klist)
>>  			pr_info("Removed event: %s\n", ent->s);
>> @@ -394,7 +398,11 @@ static int perf_del_probe_events(struct strfilter *filter)
>>  			goto error;
>>  	}
>>
>> -	ret2 = probe_file__get_events(ufd, filter, ulist);
>> +	if (ufd < 0)
>> +		ret2 = -ENOENT;
>> +	else
>> +		ret2 = probe_file__get_events(ufd, filter, ulist);
>> +
>>  	if (ret2 == 0) {
>>  		strlist__for_each(ent, ulist)
>>  			pr_info("Removed event: %s\n", ent->s);
>> --
>> 1.8.3.4
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