linux-kernel - [PATCH] selftests: seccomp: Handle syscall interruption in notification test

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Message-ID: <20251119122449.517565-1-wakel@google.com>
Date: Wed, 19 Nov 2025 20:24:49 +0800
From: Wake Liu <wakel@...gle.com>
To: Kees Cook <kees@...nel.org>, Shuah Khan <shuah@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>, Will Drewry <wad@...omium.org>, 
	linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org, 
	bpf@...r.kernel.org, Wake Liu <wakel@...gle.com>
Subject: [PATCH] selftests: seccomp: Handle syscall interruption in
 notification test

The user_notification_wait_killable_after_reply test fails due to an
unhandled error when a traced syscall is interrupted by a signal.

When a signal arrives after the tracer has received a seccomp
notification but before it has replied, the notification can become
stale. Any subsequent reply (like with SECCOMP_IOCTL_NOTIF_ADDFD)
will fail with -ENOENT.

This patch fixes the test by handling the -ENOENT return value from
SECCOMP_IOCTL_NOTIF_ADDFD, preventing the test from failing
incorrectly. The loop counter is decremented to re-run the iteration
for the restarted syscall.

Signed-off-by: Wake Liu <wakel@...gle.com>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 574fdd102eb5..c3e598c9c4ee 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -5048,8 +5048,12 @@ TEST(user_notification_wait_killable_after_reply)
 		addfd.id = req.id;
 		addfd.flags = SECCOMP_ADDFD_FLAG_SEND;
 		addfd.srcfd = 0;
-		ASSERT_GE(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), 0)
-			kill(pid, SIGKILL);
+		ret = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd);
+		if (ret < 0 && errno == ENOENT) {
+			i--;
+			continue;
+		}
+		ASSERT_GE(ret, 0);
 	}

 	/*
--
2.52.0.rc1.455.g30608eb744-goog