2021-10-04 05:53:12

by Song Liu

Subject: [PATCH] perf-script: check session->header.env.arch before using it

When perf.data is not written cleanly, we would like to process existing
data as much as possible (please see f_header.data.size == 0 condition
in perf_session__read_header). However, perf.data with partial data may
crash perf. Specifically, we see crash in perf-script for NULL
session->header.env.arch.

Fix this by checking session->header.env.arch before using it to determine
native_arch. Also split the if condition so it is easier to read.

Cc: [email protected]
Signed-off-by: Song Liu <[email protected]>
---
tools/perf/builtin-script.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 6211d0b84b7a6..7821f6740ac1d 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
goto out_delete;

uname(&uts);
- if (data.is_pipe || /* assume pipe_mode indicates native_arch */
- !strcmp(uts.machine, session->header.env.arch) ||
- (!strcmp(uts.machine, "x86_64") &&
- !strcmp(session->header.env.arch, "i386")))
+ if (data.is_pipe) /* assume pipe_mode indicates native_arch */
native_arch = true;

+ if (session->header.env.arch) {
+ if (!strcmp(uts.machine, session->header.env.arch))
+ native_arch = true;
+ else if (!strcmp(uts.machine, "x86_64") &&
+ !strcmp(session->header.env.arch, "i386"))
+ native_arch = true;
+ }
+
script.session = session;
script__setup_sample_type(&script);

--
2.30.2

2021-10-18 03:26:29

by Song Liu

Subject: Re: [PATCH] perf-script: check session->header.env.arch before using it

Hi Arnaldo,

Could you please share your comments on this one?

Thanks,
Song

> On Oct 3, 2021, at 10:32 PM, Song Liu <[email protected]> wrote:
>
> When perf.data is not written cleanly, we would like to process existing
> data as much as possible (please see f_header.data.size == 0 condition
> in perf_session__read_header). However, perf.data with partial data may
> crash perf. Specifically, we see crash in perf-script for NULL
> session->header.env.arch.
>
> Fix this by checking session->header.env.arch before using it to determine
> native_arch. Also split the if condition so it is easier to read.
>
> Cc: [email protected]
> Signed-off-by: Song Liu <[email protected]>
> ---
> tools/perf/builtin-script.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index 6211d0b84b7a6..7821f6740ac1d 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
> goto out_delete;
>
> uname(&uts);
> - if (data.is_pipe || /* assume pipe_mode indicates native_arch */
> - !strcmp(uts.machine, session->header.env.arch) ||
> - (!strcmp(uts.machine, "x86_64") &&
> - !strcmp(session->header.env.arch, "i386")))
> + if (data.is_pipe) /* assume pipe_mode indicates native_arch */
> native_arch = true;
>
> + if (session->header.env.arch) {
> + if (!strcmp(uts.machine, session->header.env.arch))
> + native_arch = true;
> + else if (!strcmp(uts.machine, "x86_64") &&
> + !strcmp(session->header.env.arch, "i386"))
> + native_arch = true;
> + }
> +
> script.session = session;
> script__setup_sample_type(&script);
>
> --
> 2.30.2
>

2021-10-27 21:26:03

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf-script: check session->header.env.arch before using it

Em Sun, Oct 03, 2021 at 10:32:38PM -0700, Song Liu escreveu:
> When perf.data is not written cleanly, we would like to process existing
> data as much as possible (please see f_header.data.size == 0 condition
> in perf_session__read_header). However, perf.data with partial data may
> crash perf. Specifically, we see crash in perf-script for NULL
> session->header.env.arch.
>
> Fix this by checking session->header.env.arch before using it to determine
> native_arch. Also split the if condition so it is easier to read.
>
> Cc: [email protected]
> Signed-off-by: Song Liu <[email protected]>
> ---
> tools/perf/builtin-script.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index 6211d0b84b7a6..7821f6740ac1d 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
> goto out_delete;
>
> uname(&uts);
> - if (data.is_pipe || /* assume pipe_mode indicates native_arch */
> - !strcmp(uts.machine, session->header.env.arch) ||
> - (!strcmp(uts.machine, "x86_64") &&
> - !strcmp(session->header.env.arch, "i386")))
> + if (data.is_pipe) /* assume pipe_mode indicates native_arch */
> native_arch = true;
>
> + if (session->header.env.arch) {

Shouldn't the above be:

else if (session->header.env.arch) {

?

> + if (!strcmp(uts.machine, session->header.env.arch))
> + native_arch = true;
> + else if (!strcmp(uts.machine, "x86_64") &&
> + !strcmp(session->header.env.arch, "i386"))
> + native_arch = true;
> + }
> +
> script.session = session;
> script__setup_sample_type(&script);
>
> --
> 2.30.2

--

- Arnaldo

2021-10-27 21:33:03

by Song Liu

Subject: Re: [PATCH] perf-script: check session->header.env.arch before using it

> On Oct 27, 2021, at 5:39 AM, Arnaldo Carvalho de Melo <[email protected]> wrote:
>
> Em Sun, Oct 03, 2021 at 10:32:38PM -0700, Song Liu escreveu:
>> When perf.data is not written cleanly, we would like to process existing
>> data as much as possible (please see f_header.data.size == 0 condition
>> in perf_session__read_header). However, perf.data with partial data may
>> crash perf. Specifically, we see crash in perf-script for NULL
>> session->header.env.arch.
>>
>> Fix this by checking session->header.env.arch before using it to determine
>> native_arch. Also split the if condition so it is easier to read.
>>
>> Cc: [email protected]
>> Signed-off-by: Song Liu <[email protected]>
>> ---
>> tools/perf/builtin-script.c | 13 +++++++++----
>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>> index 6211d0b84b7a6..7821f6740ac1d 100644
>> --- a/tools/perf/builtin-script.c
>> +++ b/tools/perf/builtin-script.c
>> @@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
>> goto out_delete;
>>
>> uname(&uts);
>> - if (data.is_pipe || /* assume pipe_mode indicates native_arch */
>> - !strcmp(uts.machine, session->header.env.arch) ||
>> - (!strcmp(uts.machine, "x86_64") &&
>> - !strcmp(session->header.env.arch, "i386")))
>> + if (data.is_pipe) /* assume pipe_mode indicates native_arch */
>> native_arch = true;
>>
>> + if (session->header.env.arch) {
>
> Shouldn't the above be:
>
> else if (session->header.env.arch) {
>
> ?

Yes! That's better.

Do you want me to send v2 with the change?

Thanks,
Song

>
>> + if (!strcmp(uts.machine, session->header.env.arch))
>> + native_arch = true;
>> + else if (!strcmp(uts.machine, "x86_64") &&
>> + !strcmp(session->header.env.arch, "i386"))
>> + native_arch = true;
>> + }
>> +
>> script.session = session;
>> script__setup_sample_type(&script);
>>
>> --
>> 2.30.2
>
> --
>
> - Arnaldo

2021-10-27 21:33:05

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf-script: check session->header.env.arch before using it

On October 27, 2021 1:41:50 PM GMT-03:00, Song Liu <[email protected]> wrote:
>
>
>> On Oct 27, 2021, at 5:39 AM, Arnaldo Carvalho de Melo <[email protected]> wrote:
>>
>> Em Sun, Oct 03, 2021 at 10:32:38PM -0700, Song Liu escreveu:
>>> When perf.data is not written cleanly, we would like to process existing
>>> data as much as possible (please see f_header.data.size == 0 condition
>>> in perf_session__read_header). However, perf.data with partial data may
>>> crash perf. Specifically, we see crash in perf-script for NULL
>>> session->header.env.arch.
>>>
>>> Fix this by checking session->header.env.arch before using it to determine
>>> native_arch. Also split the if condition so it is easier to read.
>>>
>>> Cc: [email protected]
>>> Signed-off-by: Song Liu <[email protected]>
>>> ---
>>> tools/perf/builtin-script.c | 13 +++++++++----
>>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>>> index 6211d0b84b7a6..7821f6740ac1d 100644
>>> --- a/tools/perf/builtin-script.c
>>> +++ b/tools/perf/builtin-script.c
>>> @@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
>>> goto out_delete;
>>>
>>> uname(&uts);
>>> - if (data.is_pipe || /* assume pipe_mode indicates native_arch */
>>> - !strcmp(uts.machine, session->header.env.arch) ||
>>> - (!strcmp(uts.machine, "x86_64") &&
>>> - !strcmp(session->header.env.arch, "i386")))
>>> + if (data.is_pipe) /* assume pipe_mode indicates native_arch */
>>> native_arch = true;
>>>
>>> + if (session->header.env.arch) {
>>
>> Shouldn't the above be:
>>
>> else if (session->header.env.arch) {
>>
>> ?
>
>Yes! That's better.
>
>Do you want me to send v2 with the change?


No need, it's simple enough, I'll do it myself,

- Arnaldo
>
>Thanks,
>Song
>
>>
>>> + if (!strcmp(uts.machine, session->header.env.arch))
>>> + native_arch = true;
>>> + else if (!strcmp(uts.machine, "x86_64") &&
>>> + !strcmp(session->header.env.arch, "i386"))
>>> + native_arch = true;
>>> + }
>>> +
>>> script.session = session;
>>> script__setup_sample_type(&script);
>>>
>>> --
>>> 2.30.2
>>
>> --
>>
>> - Arnaldo
>