[PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[guojian]

From: Jian Guo <guojian@kylinos.cn>

The test_cgcore_no_internal_process_constraint_on_threads test has two
back-to-back cg_enter_current(root) calls in its cleanup path.

A single cg_enter_current() call atomically migrates the entire thread
group to the target cgroup even for multi-threaded processes, and this
test creates no extra threads or child processes that would require a
second migration attempt. The second call is a harmless no-op once the
process is already in the root cgroup, but it is redundant and
inconsistent with the cleanup logic used in all other cgroup core
selftest cases.

Remove the duplicate call to clean up the code. No functional change is
intended.

Signed-off-by: Jian Guo <guojian@kylinos.cn>
---
 tools/testing/selftests/cgroup/test_core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
index 88ca832d4fc1..8e3f9b391e44 100644
--- a/tools/testing/selftests/cgroup/test_core.c
+++ b/tools/testing/selftests/cgroup/test_core.c
@@ -426,7 +426,6 @@ static int test_cgcore_no_internal_process_constraint_on_threads(const char *roo
 	ret = KSFT_PASS;
 
 cleanup:
-	cg_enter_current(root);
 	cg_enter_current(root);
 	if (child)
 		cg_destroy(child);
-- 
2.43.0

Re: [PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[Tao Cui]

在 2026/7/17 19:06, guojian 写道:
> From: Jian Guo <guojian@kylinos.cn>
> 
> The test_cgcore_no_internal_process_constraint_on_threads test has two
> back-to-back cg_enter_current(root) calls in its cleanup path.
> 
> A single cg_enter_current() call atomically migrates the entire thread
> group to the target cgroup even for multi-threaded processes, and this
> test creates no extra threads or child processes that would require a
> second migration attempt. The second call is a harmless no-op once the
> process is already in the root cgroup, but it is redundant and
> inconsistent with the cleanup logic used in all other cgroup core
> selftest cases.
> 
> Remove the duplicate call to clean up the code. No functional change is
> intended.
> 
> Signed-off-by: Jian Guo <guojian@kylinos.cn>
> ---
>  tools/testing/selftests/cgroup/test_core.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
> index 88ca832d4fc1..8e3f9b391e44 100644
> --- a/tools/testing/selftests/cgroup/test_core.c
> +++ b/tools/testing/selftests/cgroup/test_core.c
> @@ -426,7 +426,6 @@ static int test_cgcore_no_internal_process_constraint_on_threads(const char *roo
>  	ret = KSFT_PASS;
>  
>  cleanup:
> -	cg_enter_current(root);
>  	cg_enter_current(root);
>  	if (child)
>  		cg_destroy(child);

Ran test_core on x86_64 (cgroup v2, all controllers available),
12/12 pass, 0 fail, 0 skip — output byte-identical before and
after the patch. Confirms the removed call is a no-op.

Acked-by: Tao Cui <cuitao@kylinos.cn>

Thanks,
Tao

Re: [PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[Tao Cui]

于 2026年7月17日 GMT+08:00 20:51:58，Tao Cui <cui.tao@linux.dev> 写道：
>
>
>在 2026/7/17 19:06, guojian 写道:
>> From: Jian Guo <guojian@kylinos.cn>
>> 
>> The test_cgcore_no_internal_process_constraint_on_threads test has two
>> back-to-back cg_enter_current(root) calls in its cleanup path.
>> 
>> A single cg_enter_current() call atomically migrates the entire thread
>> group to the target cgroup even for multi-threaded processes, and this
>> test creates no extra threads or child processes that would require a
>> second migration attempt. The second call is a harmless no-op once the
>> process is already in the root cgroup, but it is redundant and
>> inconsistent with the cleanup logic used in all other cgroup core
>> selftest cases.
>> 
>> Remove the duplicate call to clean up the code. No functional change is
>> intended.
>> 
>> Signed-off-by: Jian Guo <guojian@kylinos.cn>
>> ---
>>  tools/testing/selftests/cgroup/test_core.c | 1 -
>>  1 file changed, 1 deletion(-)
>> 
>> diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
>> index 88ca832d4fc1..8e3f9b391e44 100644
>> --- a/tools/testing/selftests/cgroup/test_core.c
>> +++ b/tools/testing/selftests/cgroup/test_core.c
>> @@ -426,7 +426,6 @@ static int test_cgcore_no_internal_process_constraint_on_threads(const char *roo
>>  	ret = KSFT_PASS;
>>  
>>  cleanup:
>> -	cg_enter_current(root);
>>  	cg_enter_current(root);
>>  	if (child)
>>  		cg_destroy(child);
>
>Ran test_core on x86_64 (cgroup v2, all controllers available),
>12/12 pass, 0 fail, 0 skip — output byte-identical before and
>after the patch. Confirms the removed call is a no-op.
>
>Acked-by: Tao Cui <cuitao@kylinos.cn>
>

Hi,

Correction to my previous reply:

Ran test_core on x86_64 (cgroup v2, all controllers available),
12/12 pass, 0 fail, 0 skip — output byte-identical before and after the patch. Confirms the removed call is a no-op.

Tested-by: Tao Cui <cuitao@kylinos.cn>

Please ignore the earlier Acked-by tag.

Thanks,
Tao

>Thanks,
>Tao

Re: [PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[Michal Koutný]

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On Fri, Jul 17, 2026 at 07:06:06PM +0800, guojian <guojian@kylinos.cn> wrote:
> From: Jian Guo <guojian@kylinos.cn>
> 
> The test_cgcore_no_internal_process_constraint_on_threads test has two
> back-to-back cg_enter_current(root) calls in its cleanup path.
> 
> A single cg_enter_current() call atomically migrates the entire thread
> group to the target cgroup even for multi-threaded processes, and this
> test creates no extra threads or child processes that would require a
> second migration attempt. The second call is a harmless no-op once the
> process is already in the root cgroup, but it is redundant and
> inconsistent with the cleanup logic used in all other cgroup core
> selftest cases.
> 
> Remove the duplicate call to clean up the code. No functional change is
> intended.
> 
> Signed-off-by: Jian Guo <guojian@kylinos.cn>
> ---
>  tools/testing/selftests/cgroup/test_core.c | 1 -
>  1 file changed, 1 deletion(-)

Fixes: d863cb03fc5f9 ("Add cgroup core selftests")

Good catch.

Acked-by: Michal Koutný <mkoutny@suse.com>

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Re: [PATCH] selftests/cgroup: Remove redundant cg_enter_current() call in test_core

[Tejun Heo]

Hello,

Applied to cgroup/for-7.3 with Michal's ack and Tao's tested-by added.

Thanks.

-- 
tejun