[LTP] LTP in valgrind :)

[LTP] LTP in valgrind :)

[Petr Vorel]

Hi all,

in case you haven't read the news in LWN, LTP is now part of valgrind [1]:

	The Linux Test Project (ltp) is integrated in the testsuite try
	'make ltpchecks' (this will take a while and will point out various
	missing syscalls and valgrind crashes!)

FYI script they use [2]. They consider some test long running [3].

Kind regards,
Petr

[1] https://www.mail-archive.com/valgrind-users@lists.sourceforge.net/msg07691.html
[2] https://sourceware.org/git/?p=valgrind.git;a=blob;f=auxprogs/ltp-tester.sh;h=000cfaa7f336f8641f464d107a363af24f607614;hb=HEAD
[3] https://sourceware.org/git/?p=valgrind.git;a=blob;f=auxprogs/ltp-error-patterns.txt;h=ee5048bf42b652258fb469a632fb2d16afb72c38;hb=HEAD

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Re: [LTP] LTP in valgrind :)

[Andrea Cervesato via ltp]

Hi Petr,

what a nice surprise :-) I guess polishing and fixing LTP somehow helped.

Kind regards,
Andrea Cervesato

On 4/29/25 07:22, Petr Vorel wrote:
> Hi all,
>
> in case you haven't read the news in LWN, LTP is now part of valgrind [1]:
>
> 	The Linux Test Project (ltp) is integrated in the testsuite try
> 	'make ltpchecks' (this will take a while and will point out various
> 	missing syscalls and valgrind crashes!)
>
> FYI script they use [2]. They consider some test long running [3].
>
> Kind regards,
> Petr
>
> [1] https://www.mail-archive.com/valgrind-users@lists.sourceforge.net/msg07691.html
> [2] https://sourceware.org/git/?p=valgrind.git;a=blob;f=auxprogs/ltp-tester.sh;h=000cfaa7f336f8641f464d107a363af24f607614;hb=HEAD
> [3] https://sourceware.org/git/?p=valgrind.git;a=blob;f=auxprogs/ltp-error-patterns.txt;h=ee5048bf42b652258fb469a632fb2d16afb72c38;hb=HEAD
>

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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
Awesome :-)

It also opens some interesting questions, i.e. how do we make comparing
results from two different tests easier. Currently they grep the test
results for a summary, but maybe we can do better.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] LTP in valgrind :)

[Martin Doucha]

On 02. 05. 25 11:49, Cyril Hrubis wrote:
> Hi!
> Awesome :-)
> 
> It also opens some interesting questions, i.e. how do we make comparing
> results from two different tests easier. Currently they grep the test
> results for a summary, but maybe we can do better.

One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages, 
discard any message contents past the file:line header and then compare 
whether the sanitized output is identical. That'll take care of random 
values in the output while ensuring that the test went through the same 
code paths as before. We could provide a sanitizer script for that.

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic

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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
> > It also opens some interesting questions, i.e. how do we make comparing
> > results from two different tests easier. Currently they grep the test
> > results for a summary, but maybe we can do better.
> 
> One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages, 
> discard any message contents past the file:line header and then compare 
> whether the sanitized output is identical. That'll take care of random 
> values in the output while ensuring that the test went through the same 
> code paths as before. We could provide a sanitizer script for that.

Maybe we can even add an option to the test library to supress the
messages in output, that would be fairly simple.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] LTP in valgrind :)

[Petr Vorel]

> Hi!
> > > It also opens some interesting questions, i.e. how do we make comparing
> > > results from two different tests easier. Currently they grep the test
> > > results for a summary, but maybe we can do better.

> > One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages, 
> > discard any message contents past the file:line header and then compare 
> > whether the sanitized output is identical. That'll take care of random 
> > values in the output while ensuring that the test went through the same 
> > code paths as before. We could provide a sanitizer script for that.

> Maybe we can even add an option to the test library to supress the
> messages in output, that would be fairly simple.

+1

And Cc the authors :).

Kind regards,
Petr

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Re: [LTP] LTP in valgrind :)

[Petr Vorel]

Hi all,

[ Cc Martin and Mark from Valgrind project ]

> Hi!
> > > It also opens some interesting questions, i.e. how do we make comparing
> > > results from two different tests easier. Currently they grep the test
> > > results for a summary, but maybe we can do better.

> > One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages, 
> > discard any message contents past the file:line header and then compare 
> > whether the sanitized output is identical. That'll take care of random 
> > values in the output while ensuring that the test went through the same 
> > code paths as before. We could provide a sanitizer script for that.

> Maybe we can even add an option to the test library to supress the
> messages in output, that would be fairly simple.

@Martin @Mark: feel free to comment what we can do for you :).
Whole thread:
https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t

Kind regards,
Petr

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Re: [LTP] LTP in valgrind :)

[Martin Cermak via ltp]

Hello guys,

On  Tue  2025-05-06  10:05 , Petr Vorel wrote:
> Hi all,
>
> [ Cc Martin and Mark from Valgrind project ]
>
> > Hi!
> > > > It also opens some interesting questions, i.e. how do we make comparing
> > > > results from two different tests easier. Currently they grep the test
> > > > results for a summary, but maybe we can do better.
>
> > > One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages,
> > > discard any message contents past the file:line header and then compare
> > > whether the sanitized output is identical. That'll take care of random
> > > values in the output while ensuring that the test went through the same
> > > code paths as before. We could provide a sanitizer script for that.
>
> > Maybe we can even add an option to the test library to supress the
> > messages in output, that would be fairly simple.
>
> @Martin @Mark: feel free to comment what we can do for you :).
> Whole thread:
> https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t

Nice to see you noticed!  Primarily we're trying to identify
valgrind gaps and bugs.  For our use-case it's good to have
reproducible test runs in a sense of identical test results for
repeated test runs.  We got pretty close to this by only taking
into account the testcase summaries at the very end of the test
logs.  Any steps to get closer to reproducible test runs on the
LTP side are interesting for us, and we'll try to reflect those!

Cheers,
Martin


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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
> > > > > It also opens some interesting questions, i.e. how do we make comparing
> > > > > results from two different tests easier. Currently they grep the test
> > > > > results for a summary, but maybe we can do better.
> >
> > > > One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages,
> > > > discard any message contents past the file:line header and then compare
> > > > whether the sanitized output is identical. That'll take care of random
> > > > values in the output while ensuring that the test went through the same
> > > > code paths as before. We could provide a sanitizer script for that.
> >
> > > Maybe we can even add an option to the test library to supress the
> > > messages in output, that would be fairly simple.
> >
> > @Martin @Mark: feel free to comment what we can do for you :).
> > Whole thread:
> > https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t
> 
> Nice to see you noticed!  Primarily we're trying to identify
> valgrind gaps and bugs.  For our use-case it's good to have
> reproducible test runs in a sense of identical test results for
> repeated test runs.  We got pretty close to this by only taking
> into account the testcase summaries at the very end of the test
> logs.  Any steps to get closer to reproducible test runs on the
> LTP side are interesting for us, and we'll try to reflect those!

I've proposed a simple solution that would cut the message from tests
only to contain the line numbers and results in:

https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#m98317262b25ede62704b005fcefc63c62198bb90

If that works for you we can get this in LTP before the next release.

-- 
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chrubis@suse.cz

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Re: [LTP] LTP in valgrind :)

[Mark Wielaard]

Hi Cyril, Hi ltp hackers,

On Wed, 2025-05-07 at 17:29 +0200, Cyril Hrubis wrote:
> > > > > 
> > > > Maybe we can even add an option to the test library to supress the
> > > > messages in output, that would be fairly simple.
> > > 
> > > @Martin @Mark: feel free to comment what we can do for you :).
> > > Whole thread:
> > > https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t
> > 
> > Nice to see you noticed!  Primarily we're trying to identify
> > valgrind gaps and bugs.  For our use-case it's good to have
> > reproducible test runs in a sense of identical test results for
> > repeated test runs.  We got pretty close to this by only taking
> > into account the testcase summaries at the very end of the test
> > logs.  Any steps to get closer to reproducible test runs on the
> > LTP side are interesting for us, and we'll try to reflect those!
> 
> I've proposed a simple solution that would cut the message from tests
> only to contain the line numbers and results in:
> 
> https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#m98317262b25ede62704b005fcefc63c62198bb90
> 
> If that works for you we can get this in LTP before the next release.
> 

That looks pretty interesting, I just tried it and it turns:

$ ./testcases/kernel/syscalls/dup/dup01 
tst_tmpdir.c:316: TINFO: Using /tmp/LTP_dupbmNNGn as tmpdir (tmpfs filesystem)
tst_test.c:1907: TINFO: LTP version: VALGRIND_3_25_0-10-g0ce068434ec3
tst_test.c:1911: TINFO: Tested kernel: 6.13.11-200.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Apr 10 19:02:09 UTC 2025 x86_64
tst_kconfig.c:88: TINFO: Parsing kernel config '/lib/modules/6.13.11-200.fc41.x86_64/build/.config'
tst_test.c:1729: TINFO: Overall timeout per run is 0h 00m 30s
dup01.c:24: TPASS: dup(fd) returned fd 4
dup01.c:27: TPASS: buf1.st_ino == buf2.st_ino (6921515)

Summary:
passed   2
failed   0
broken   0
skipped  0
warnings 0

into:

$ LTP_REPRODUCIBLE_OUTPUT=1 ./testcases/kernel/syscalls/dup/dup01 
tst_tmpdir.c:316: 
tst_test.c:1907: 
tst_test.c:1911: 
tst_kconfig.c:88: 
tst_test.c:1729: 
dup01.c:24: 
dup01.c:27: 

Summary:
passed   2
failed   0
broken   0
skipped  0
warnings 0

So that still shows the "code flow" and the test results Summary (all
output goes to stderr). I think this would indeed be useful to compare
if a testcase runs the same "native" and under valgrind.

Thanks,

Mark

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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
> That looks pretty interesting, I just tried it and it turns:
> 
> $ ./testcases/kernel/syscalls/dup/dup01 
> tst_tmpdir.c:316: TINFO: Using /tmp/LTP_dupbmNNGn as tmpdir (tmpfs filesystem)
> tst_test.c:1907: TINFO: LTP version: VALGRIND_3_25_0-10-g0ce068434ec3
> tst_test.c:1911: TINFO: Tested kernel: 6.13.11-200.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Apr 10 19:02:09 UTC 2025 x86_64
> tst_kconfig.c:88: TINFO: Parsing kernel config '/lib/modules/6.13.11-200.fc41.x86_64/build/.config'
> tst_test.c:1729: TINFO: Overall timeout per run is 0h 00m 30s
> dup01.c:24: TPASS: dup(fd) returned fd 4
> dup01.c:27: TPASS: buf1.st_ino == buf2.st_ino (6921515)
> 
> Summary:
> passed   2
> failed   0
> broken   0
> skipped  0
> warnings 0
> 
> into:
> 
> $ LTP_REPRODUCIBLE_OUTPUT=1 ./testcases/kernel/syscalls/dup/dup01 
> tst_tmpdir.c:316: 
> tst_test.c:1907: 
> tst_test.c:1911: 
> tst_kconfig.c:88: 
> tst_test.c:1729: 
> dup01.c:24: 
> dup01.c:27: 
> 
> Summary:
> passed   2
> failed   0
> broken   0
> skipped  0
> warnings 0
> 
> So that still shows the "code flow" and the test results Summary (all
> output goes to stderr). I think this would indeed be useful to compare
> if a testcase runs the same "native" and under valgrind.

I will send a proper LTP patch.

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Re: [LTP] LTP in valgrind :)

[Bird, Tim]

> -----Original Message-----
> From: ltp <ltp-bounces+tim.bird=sony.com@lists.linux.it> On Behalf Of Mark Wielaard
> Hi Cyril, Hi ltp hackers,
> 
> On Wed, 2025-05-07 at 17:29 +0200, Cyril Hrubis wrote:
> > > > > >
> > > > > Maybe we can even add an option to the test library to supress the
> > > > > messages in output, that would be fairly simple.
> > > >
> > > > @Martin @Mark: feel free to comment what we can do for you :).
> > > > Whole thread:
> > > > https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t
> > >
> > > Nice to see you noticed!  Primarily we're trying to identify
> > > valgrind gaps and bugs.  For our use-case it's good to have
> > > reproducible test runs in a sense of identical test results for
> > > repeated test runs.  We got pretty close to this by only taking
> > > into account the testcase summaries at the very end of the test
> > > logs.  Any steps to get closer to reproducible test runs on the
> > > LTP side are interesting for us, and we'll try to reflect those!
> >
> > I've proposed a simple solution that would cut the message from tests
> > only to contain the line numbers and results in:
> >
> > https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#m98317262b25ede62704b005fcefc63c62198bb90
> >
> > If that works for you we can get this in LTP before the next release.
> >
> 
> That looks pretty interesting, I just tried it and it turns:
> 
> $ ./testcases/kernel/syscalls/dup/dup01
> tst_tmpdir.c:316: TINFO: Using /tmp/LTP_dupbmNNGn as tmpdir (tmpfs filesystem)
> tst_test.c:1907: TINFO: LTP version: VALGRIND_3_25_0-10-g0ce068434ec3
> tst_test.c:1911: TINFO: Tested kernel: 6.13.11-200.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Apr 10 19:02:09 UTC 2025 x86_64
> tst_kconfig.c:88: TINFO: Parsing kernel config '/lib/modules/6.13.11-200.fc41.x86_64/build/.config'
> tst_test.c:1729: TINFO: Overall timeout per run is 0h 00m 30s
> dup01.c:24: TPASS: dup(fd) returned fd 4
> dup01.c:27: TPASS: buf1.st_ino == buf2.st_ino (6921515)
> 
> Summary:
> passed   2
> failed   0
> broken   0
> skipped  0
> warnings 0
> 
> into:
> 
> $ LTP_REPRODUCIBLE_OUTPUT=1 ./testcases/kernel/syscalls/dup/dup01
> tst_tmpdir.c:316:
> tst_test.c:1907:
> tst_test.c:1911:
> tst_kconfig.c:88:
> tst_test.c:1729:
> dup01.c:24:
> dup01.c:27:

Don't you want to keep the status or result (TINFO and TPASS)?

This shouldn't change from run-to-run unless the test is flaky.

 -- Tim


> Summary:
> passed   2
> failed   0
> broken   0
> skipped  0
> warnings 0
> 
> So that still shows the "code flow" and the test results Summary (all
> output goes to stderr). I think this would indeed be useful to compare
> if a testcase runs the same "native" and under valgrind.
> 
> Thanks,
> 
> Mark
> 
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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
> Don't you want to keep the status or result (TINFO and TPASS)?
> 
> This shouldn't change from run-to-run unless the test is flaky.

Already addressed in v2 patch:

http://patchwork.ozlabs.org/project/ltp/patch/20250509092813.12860-1-chrubis@suse.cz/

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Re: [LTP] LTP in valgrind :)

[Mark Wielaard]

Hi Petr, Hi ltp hackers,

On Tue, 2025-05-06 at 10:05 +0200, Petr Vorel wrote:
> > > > It also opens some interesting questions, i.e. how do we make comparing
> > > > results from two different tests easier. Currently they grep the test
> > > > results for a summary, but maybe we can do better.
> 
> > > One option is to extract all TPASS/TFAIL/TWARN/TBROK/TCONF messages, 
> > > discard any message contents past the file:line header and then compare 
> > > whether the sanitized output is identical. That'll take care of random 
> > > values in the output while ensuring that the test went through the same 
> > > code paths as before. We could provide a sanitizer script for that.
> 
> > Maybe we can even add an option to the test library to supress the
> > messages in output, that would be fairly simple.
> 
> @Martin @Mark: feel free to comment what we can do for you :).
> Whole thread:
> https://lore.kernel.org/ltp/20250505195003.GB137650@pevik/T/#t

Thanks. Something small, but if you could CC
valgrind-developers@lists.sourceforge.net on new ltp releases that
would be great.

I saw a question at the top of that thread about "They consider some
test long running". In general that is not about the actual ltp tests
(we currently only run the testcases/kernel/syscalls ones), but because
valgrind:

a) is basically a giant Just In Time compiler, which instruments all
code, and might slow down your code 20x (yeah, we know).

b) serializes all threads, so only one thread runs at a time, all
parallel code is executed as if it was serial code.

c) memcheck keeps track of all memory to see if values are "valid"
(have a known value written to them). This cost about 25% more memory
than the program itself uses (and might actually double the amount).

So for now we have the following exclude file:
https://sourceware.org/cgit/valgrind/tree/auxprogs/ltp-excludes.txt

bind06
epoll-ltp
fork14
futex_cmp_requeue01
futex_cmp_requeue02
inotify09
msgstress01
pidfd_send_signal01
pidfd_send_signal02
pidfd_send_signal03
sendmsg03
setsockopt06
setsockopt07
signal05
signal06
timerfd_settime02

We haven't yet analyzed them to see what exactly makes them so slow
(under valgrind). It was more important to get the ltpchecks run on all
our CI systems:
https://builder.sourceware.org/buildbot/#/builders?tags=valgrind
Some of those systems only have 8GB of memory or are fairly slow
(specifically the arm32 and riscv builders).

The pidfd_send_signal tests are excluded because they seemed to kill
the container they were running inside. Again, this could be a valgrind
bug. valgrind doesn't implement a proper syscall wrapper for
pidfd_send_signal so it might be possible we are just killing a random
process...

Cheers,

Mark

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Re: [LTP] LTP in valgrind :)

[Petr Vorel]

> Hi!
> Awesome :-)

> It also opens some interesting questions, i.e. how do we make comparing
> results from two different tests easier. Currently they grep the test
> results for a summary, but maybe we can do better.

Kirk and compare json?

Kind regards,
Petr

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Re: [LTP] LTP in valgrind :)

[Cyril Hrubis]

Hi!
> > It also opens some interesting questions, i.e. how do we make comparing
> > results from two different tests easier. Currently they grep the test
> > results for a summary, but maybe we can do better.
> 
> Kirk and compare json?

That does sound like an overkill for something that is basically:

diff --git a/lib/tst_test.c b/lib/tst_test.c
index 694861d95..29d9fc1d5 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -64,6 +64,7 @@ static int mntpoint_mounted;
 static int ovl_mounted;
 static struct timespec tst_start_time; /* valid only for test pid */
 static int tdebug;
+static int reproducible_output;

 struct results {
        int passed;
@@ -299,6 +300,9 @@ static void print_result(const char *file, const int lineno, int ttype,
        str += ret;
        size -= ret;

+       if (reproducible_output)
+               goto print;
+
        if (tst_color_enabled(STDERR_FILENO))
                ret = snprintf(str, size, "%s%s: %s", tst_ttype2color(ttype),
                               res, ANSI_COLOR_RESET);
@@ -324,6 +328,7 @@ static void print_result(const char *file, const int lineno, int ttype,
                                "Next message is too long and truncated:");
        }

+print:
        snprintf(str, size, "\n");

        /* we might be called from signal handler, so use write() */
@@ -1273,6 +1278,8 @@ static void do_setup(int argc, char *argv[])
        if (tst_test->tconf_msg)
                tst_brk(TCONF, "%s", tst_test->tconf_msg);

+       reproducible_output = !!getenv("LTP_REPRODUCIBLE_OUTPUT");
+
        assert_test_fn();

        TCID = tid = get_tid(argv);


-- 
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chrubis@suse.cz

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Re: [LTP] LTP in valgrind :)

[Petr Vorel]

Hi Cyril,

> Hi!
> > > It also opens some interesting questions, i.e. how do we make comparing
> > > results from two different tests easier. Currently they grep the test
> > > results for a summary, but maybe we can do better.

> > Kirk and compare json?

> That does sound like an overkill for something that is basically:

Agree. I sometimes think JSON output would be useful to be even in core LTP
(not requiring kirk), but that's something different than reproducible output.

The patch above LGTM (if you send patch please remember to update
doc/users/setup_tests.rst).

Kind regards,
Petr

> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 694861d95..29d9fc1d5 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -64,6 +64,7 @@ static int mntpoint_mounted;
>  static int ovl_mounted;
>  static struct timespec tst_start_time; /* valid only for test pid */
>  static int tdebug;
> +static int reproducible_output;

>  struct results {
>         int passed;
> @@ -299,6 +300,9 @@ static void print_result(const char *file, const int lineno, int ttype,
>         str += ret;
>         size -= ret;

> +       if (reproducible_output)
> +               goto print;
> +
>         if (tst_color_enabled(STDERR_FILENO))
>                 ret = snprintf(str, size, "%s%s: %s", tst_ttype2color(ttype),
>                                res, ANSI_COLOR_RESET);
> @@ -324,6 +328,7 @@ static void print_result(const char *file, const int lineno, int ttype,
>                                 "Next message is too long and truncated:");
>         }

> +print:
>         snprintf(str, size, "\n");

>         /* we might be called from signal handler, so use write() */
> @@ -1273,6 +1278,8 @@ static void do_setup(int argc, char *argv[])
>         if (tst_test->tconf_msg)
>                 tst_brk(TCONF, "%s", tst_test->tconf_msg);

> +       reproducible_output = !!getenv("LTP_REPRODUCIBLE_OUTPUT");
> +
>         assert_test_fn();

>         TCID = tid = get_tid(argv);

-- 
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