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[PATCH bpf-next v2 5/5] selftests/bpf: Fix arena_spin_lock selftest failure

Saket Kumar Bhaskar posted 5 patches 1 month ago
There is a newer version of this series
[PATCH bpf-next v2 5/5] selftests/bpf: Fix arena_spin_lock selftest failure
Posted by Saket Kumar Bhaskar 1 month ago 
For systems having CONFIG_NR_CPUS set to > 1024 in kernel config
the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP.

The selftest is skipped incase bpf program returns EOPNOTSUPP,
with a descriptive message logged.

Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
---
 .../selftests/bpf/prog_tests/arena_spin_lock.c      | 13 +++++++++++++
 tools/testing/selftests/bpf/progs/arena_spin_lock.c |  5 ++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
index 0223fce4db2b..1ec1ca987893 100644
--- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
+++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
@@ -40,8 +40,13 @@ static void *spin_lock_thread(void *arg)
 
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
 	ASSERT_OK(err, "test_run err");
+
+	if (topts.retval == -EOPNOTSUPP)
+		goto end;
+
 	ASSERT_EQ((int)topts.retval, 0, "test_run retval");
 
+end:
 	pthread_exit(arg);
 }
 
@@ -63,6 +68,7 @@ static void test_arena_spin_lock_size(int size)
 	skel = arena_spin_lock__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "arena_spin_lock__open_and_load"))
 		return;
+
 	if (skel->data->test_skip == 2) {
 		test__skip();
 		goto end;
@@ -86,6 +92,13 @@ static void test_arena_spin_lock_size(int size)
 			goto end_barrier;
 	}
 
+	if (skel->data->test_skip == 2) {
+		printf("%s:SKIP: %d CPUs exceed the maximum supported by arena spinlock\n",
+		       __func__, get_nprocs());
+		test__skip();
+		goto end_barrier;
+	}
+
 	ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value");
 
 end_barrier:
diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
index c4500c37f85e..a475b974438e 100644
--- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
+++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
@@ -37,8 +37,11 @@ int prog(void *ctx)
 #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
 	unsigned long flags;
 
-	if ((ret = arena_spin_lock_irqsave(&lock, flags)))
+	if ((ret = arena_spin_lock_irqsave(&lock, flags))) {
+		if (ret == -EOPNOTSUPP)
+			test_skip = 2;
 		return ret;
+	}
 	if (counter != limit)
 		counter++;
 	bpf_repeat(cs_count);
-- 
2.43.5
Re: [PATCH bpf-next v2 5/5] selftests/bpf: Fix arena_spin_lock selftest failure
Posted by Hari Bathini 4 weeks, 1 day ago 

On 29/08/25 10:21 pm, Saket Kumar Bhaskar wrote:
> For systems having CONFIG_NR_CPUS set to > 1024 in kernel config
> the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP.
> 
> The selftest is skipped incase bpf program returns EOPNOTSUPP,
> with a descriptive message logged.
> 
> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> ---
>   .../selftests/bpf/prog_tests/arena_spin_lock.c      | 13 +++++++++++++
>   tools/testing/selftests/bpf/progs/arena_spin_lock.c |  5 ++++-
>   2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> index 0223fce4db2b..1ec1ca987893 100644
> --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> @@ -40,8 +40,13 @@ static void *spin_lock_thread(void *arg)
>   
>   	err = bpf_prog_test_run_opts(prog_fd, &topts);
>   	ASSERT_OK(err, "test_run err");
> +
> +	if (topts.retval == -EOPNOTSUPP)
> +		goto end;
> +
>   	ASSERT_EQ((int)topts.retval, 0, "test_run retval");
>   
> +end:
>   	pthread_exit(arg);
>   }
>   
> @@ -63,6 +68,7 @@ static void test_arena_spin_lock_size(int size)
>   	skel = arena_spin_lock__open_and_load();
>   	if (!ASSERT_OK_PTR(skel, "arena_spin_lock__open_and_load"))
>   		return;
> +
>   	if (skel->data->test_skip == 2) {
>   		test__skip();
>   		goto end;
> @@ -86,6 +92,13 @@ static void test_arena_spin_lock_size(int size)
>   			goto end_barrier;
>   	}
>   
> +	if (skel->data->test_skip == 2) {
> +		printf("%s:SKIP: %d CPUs exceed the maximum supported by arena spinlock\n",
> +		       __func__, get_nprocs());
> +		test__skip();
> +		goto end_barrier;
> +	}
> +
>   	ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value");
>   
>   end_barrier:
> diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> index c4500c37f85e..a475b974438e 100644
> --- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> +++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> @@ -37,8 +37,11 @@ int prog(void *ctx)
>   #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
>   	unsigned long flags;
>   
> -	if ((ret = arena_spin_lock_irqsave(&lock, flags)))
> +	if ((ret = arena_spin_lock_irqsave(&lock, flags))) {
> +		if (ret == -EOPNOTSUPP)
> +			test_skip = 2;
>   		return ret;

test_skip being set to `1` when the test runs seems counter intuitive.
How about setting test_skip to `0` when run conditions are met
and test_skip=1 if run conditions are not met and
test_skip=2 when operation is not supported?

- Hari
Re: [PATCH bpf-next v2 5/5] selftests/bpf: Fix arena_spin_lock selftest failure
Posted by Saket Kumar Bhaskar 4 weeks, 1 day ago 
On Thu, Sep 04, 2025 at 01:39:31PM +0530, Hari Bathini wrote:
> 
> 
> On 29/08/25 10:21 pm, Saket Kumar Bhaskar wrote:
> > For systems having CONFIG_NR_CPUS set to > 1024 in kernel config
> > the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP.
> > 
> > The selftest is skipped incase bpf program returns EOPNOTSUPP,
> > with a descriptive message logged.
> > 
> > Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> > ---
> >   .../selftests/bpf/prog_tests/arena_spin_lock.c      | 13 +++++++++++++
> >   tools/testing/selftests/bpf/progs/arena_spin_lock.c |  5 ++++-
> >   2 files changed, 17 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > index 0223fce4db2b..1ec1ca987893 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > @@ -40,8 +40,13 @@ static void *spin_lock_thread(void *arg)
> >   	err = bpf_prog_test_run_opts(prog_fd, &topts);
> >   	ASSERT_OK(err, "test_run err");
> > +
> > +	if (topts.retval == -EOPNOTSUPP)
> > +		goto end;
> > +
> >   	ASSERT_EQ((int)topts.retval, 0, "test_run retval");
> > +end:
> >   	pthread_exit(arg);
> >   }
> > @@ -63,6 +68,7 @@ static void test_arena_spin_lock_size(int size)
> >   	skel = arena_spin_lock__open_and_load();
> >   	if (!ASSERT_OK_PTR(skel, "arena_spin_lock__open_and_load"))
> >   		return;
> > +
> >   	if (skel->data->test_skip == 2) {
> >   		test__skip();
> >   		goto end;
> > @@ -86,6 +92,13 @@ static void test_arena_spin_lock_size(int size)
> >   			goto end_barrier;
> >   	}
> > +	if (skel->data->test_skip == 2) {
> > +		printf("%s:SKIP: %d CPUs exceed the maximum supported by arena spinlock\n",
> > +		       __func__, get_nprocs());
> > +		test__skip();
> > +		goto end_barrier;
> > +	}
> > +
> >   	ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value");
> >   end_barrier:
> > diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > index c4500c37f85e..a475b974438e 100644
> > --- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > +++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > @@ -37,8 +37,11 @@ int prog(void *ctx)
> >   #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
> >   	unsigned long flags;
> > -	if ((ret = arena_spin_lock_irqsave(&lock, flags)))
> > +	if ((ret = arena_spin_lock_irqsave(&lock, flags))) {
> > +		if (ret == -EOPNOTSUPP)
> > +			test_skip = 2;
> >   		return ret;
> 
> test_skip being set to `1` when the test runs seems counter intuitive.
> How about setting test_skip to `0` when run conditions are met
> and test_skip=1 if run conditions are not met and
> test_skip=2 when operation is not supported?
> 
> - Hari
That seems reasonable to me, but right now -EOPNOTSUPP is also
returned when run condition is not met i.e.:

  if (CONFIG_NR_CPUS > 1024)
                return -EOPNOTSUPP;

So do we really need test_skip = 2 ?

Thanks,
Saket
Re: [PATCH bpf-next v2 5/5] selftests/bpf: Fix arena_spin_lock selftest failure
Posted by Saket Kumar Bhaskar 4 weeks, 1 day ago 
On Thu, Sep 04, 2025 at 01:55:40PM +0530, Saket Kumar Bhaskar wrote:
> On Thu, Sep 04, 2025 at 01:39:31PM +0530, Hari Bathini wrote:
> > 
> > 
> > On 29/08/25 10:21 pm, Saket Kumar Bhaskar wrote:
> > > For systems having CONFIG_NR_CPUS set to > 1024 in kernel config
> > > the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP.
> > > 
> > > The selftest is skipped incase bpf program returns EOPNOTSUPP,
> > > with a descriptive message logged.
> > > 
> > > Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> > > ---
> > >   .../selftests/bpf/prog_tests/arena_spin_lock.c      | 13 +++++++++++++
> > >   tools/testing/selftests/bpf/progs/arena_spin_lock.c |  5 ++++-
> > >   2 files changed, 17 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > > index 0223fce4db2b..1ec1ca987893 100644
> > > --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > > +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
> > > @@ -40,8 +40,13 @@ static void *spin_lock_thread(void *arg)
> > >   	err = bpf_prog_test_run_opts(prog_fd, &topts);
> > >   	ASSERT_OK(err, "test_run err");
> > > +
> > > +	if (topts.retval == -EOPNOTSUPP)
> > > +		goto end;
> > > +
> > >   	ASSERT_EQ((int)topts.retval, 0, "test_run retval");
> > > +end:
> > >   	pthread_exit(arg);
> > >   }
> > > @@ -63,6 +68,7 @@ static void test_arena_spin_lock_size(int size)
> > >   	skel = arena_spin_lock__open_and_load();
> > >   	if (!ASSERT_OK_PTR(skel, "arena_spin_lock__open_and_load"))
> > >   		return;
> > > +
> > >   	if (skel->data->test_skip == 2) {
> > >   		test__skip();
> > >   		goto end;
> > > @@ -86,6 +92,13 @@ static void test_arena_spin_lock_size(int size)
> > >   			goto end_barrier;
> > >   	}
> > > +	if (skel->data->test_skip == 2) {
> > > +		printf("%s:SKIP: %d CPUs exceed the maximum supported by arena spinlock\n",
> > > +		       __func__, get_nprocs());
> > > +		test__skip();
> > > +		goto end_barrier;
> > > +	}
> > > +
> > >   	ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value");
> > >   end_barrier:
> > > diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > > index c4500c37f85e..a475b974438e 100644
> > > --- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > > +++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
> > > @@ -37,8 +37,11 @@ int prog(void *ctx)
> > >   #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
> > >   	unsigned long flags;
> > > -	if ((ret = arena_spin_lock_irqsave(&lock, flags)))
> > > +	if ((ret = arena_spin_lock_irqsave(&lock, flags))) {
> > > +		if (ret == -EOPNOTSUPP)
> > > +			test_skip = 2;
> > >   		return ret;
> > 
> > test_skip being set to `1` when the test runs seems counter intuitive.
> > How about setting test_skip to `0` when run conditions are met
> > and test_skip=1 if run conditions are not met and
> > test_skip=2 when operation is not supported?
> > 
> > - Hari
> That seems reasonable to me, but right now -EOPNOTSUPP is also
> returned when run condition is not met i.e.:
> 
>   if (CONFIG_NR_CPUS > 1024)
>                 return -EOPNOTSUPP;
> 
> So do we really need test_skip = 2 ?
> 
> Thanks,
> Saket
Also, when test_skip is initialized to 0 it is moved to bss segment 
from data segment:

        struct arena_spin_lock__arena {
                struct arena_qnode qnodes[1024][4];
                struct __qspinlock lock;
        } *arena;
        struct arena_spin_lock__bss {
                int test_skip;
                int counter;
                int limit;
                int cs_count;
        } *bss;

I dont have enough background here, as to if there is any specific 
reason to keep it in data segment:

        if (skel->data->test_skip == 2) {
                test__skip();
                goto end;
        }

Thanks,
Saket

Patchew 2.1-devel-b67e4c2

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