[PATCH bpf-next] selftests/bpf: Clean up child when task_work__open() fails

[PATCH bpf-next] selftests/bpf: Clean up child when task_work__open() fails

[Yun Lu]

From: Yun Lu <luyun@kylinos.cn>

task_work_run() forks a child that blocks reading a pipe until the
parent wakes it. If task_work__open() fails afterwards, the parent
returns without closing either pipe fd or waiting for the child.
Because the parent retains the write end, the child remains blocked in
read() until test_progs exits.

Route this failure through the common cleanup path. At this point
cleanup is safe: pe_fd is -1, link is NULL, task_work__destroy() accepts
NULL, and the pid > 0 branch closes the read end, wakes the child,
closes the write end and waits for it.

This is the last early return after a successful fork. The fork failure
path already closes both pipe fds after commit 5730dacb3f17
("selftests/bpf: Task_work selftest cleanup fixes").

Fixes: 39fd74dfd5d2 ("selftests/bpf: BPF task work scheduling tests")
Signed-off-by: Yun Lu <luyun@kylinos.cn>

---
Resent as a standalone patch against bpf-next as requested during
review; the content is unchanged from patch 2/2 of the previous
series.

 tools/testing/selftests/bpf/prog_tests/test_task_work.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_work.c b/tools/testing/selftests/bpf/prog_tests/test_task_work.c
index 774b31a5f6ca..fe0cb1702eaa 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_task_work.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_task_work.c
@@ -85,7 +85,7 @@ static void task_work_run(const char *prog_name, const char *map_name)
 
 	skel = task_work__open();
 	if (!ASSERT_OK_PTR(skel, "task_work__open"))
-		return;
+		goto cleanup;
 
 	bpf_object__for_each_program(prog, skel->obj) {
 		bpf_program__set_autoload(prog, false);
-- 
2.43.0

Re: [PATCH bpf-next] selftests/bpf: Clean up child when task_work__open() fails

[Mykyta Yatsenko]

On 9/18/26 3:43 AM, Yun Lu wrote:
> From: Yun Lu <luyun@kylinos.cn>
> 
> task_work_run() forks a child that blocks reading a pipe until the
> parent wakes it. If task_work__open() fails afterwards, the parent
> returns without closing either pipe fd or waiting for the child.
> Because the parent retains the write end, the child remains blocked in
> read() until test_progs exits.
> 
> Route this failure through the common cleanup path. At this point
> cleanup is safe: pe_fd is -1, link is NULL, task_work__destroy() accepts
> NULL, and the pid > 0 branch closes the read end, wakes the child,
> closes the write end and waits for it.
> 
> This is the last early return after a successful fork. The fork failure
> path already closes both pipe fds after commit 5730dacb3f17
> ("selftests/bpf: Task_work selftest cleanup fixes").
> 
> Fixes: 39fd74dfd5d2 ("selftests/bpf: BPF task work scheduling tests")
> Signed-off-by: Yun Lu <luyun@kylinos.cn>
> 
> ---

Looks correct, thanks for the patch.
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>

> Resent as a standalone patch against bpf-next as requested during
> review; the content is unchanged from patch 2/2 of the previous
> series.
> 
>  tools/testing/selftests/bpf/prog_tests/test_task_work.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_work.c b/tools/testing/selftests/bpf/prog_tests/test_task_work.c
> index 774b31a5f6ca..fe0cb1702eaa 100644
> --- a/tools/testing/selftests/bpf/prog_tests/test_task_work.c
> +++ b/tools/testing/selftests/bpf/prog_tests/test_task_work.c
> @@ -85,7 +85,7 @@ static void task_work_run(const char *prog_name, const char *map_name)
>  
>  	skel = task_work__open();
>  	if (!ASSERT_OK_PTR(skel, "task_work__open"))
> -		return;
> +		goto cleanup;
>  
>  	bpf_object__for_each_program(prog, skel->obj) {
>  		bpf_program__set_autoload(prog, false);

Re: [PATCH bpf-next] selftests/bpf: Clean up child when task_work__open() fails

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Fri, 18 Sep 2026 10:43:00 +0800 you wrote:
> From: Yun Lu <luyun@kylinos.cn>
> 
> task_work_run() forks a child that blocks reading a pipe until the
> parent wakes it. If task_work__open() fails afterwards, the parent
> returns without closing either pipe fd or waiting for the child.
> Because the parent retains the write end, the child remains blocked in
> read() until test_progs exits.
> 
> [...]

Here is the summary with links:
  - [bpf-next] selftests/bpf: Clean up child when task_work__open() fails
    https://git.kernel.org/bpf/bpf-next/c/8715b13c1a80

You are awesome, thank you!
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