From: Karel Zak <kzak@redhat.com>
Date: Tue, 16 Jun 2026 07:24:40 +0000 (+0200)
Subject: tests: handle ENOSYS in multiplexing syscall tests
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5370abcc8d4a1c0f2d5a5fd1db0aee51f81fd6c0;p=thirdparty%2Futil-linux.git

tests: handle ENOSYS in multiplexing syscall tests

On ppc64le, __NR_select is defined at compile time, so test_mkfds -W
lists "select" as available. However, the kernel returns ENOSYS at
runtime. The helper process prints its PID, then calls select() which
fails immediately with ENOSYS. This creates a race where the bash
script's kill -0 liveness check can succeed while the process is
still dying, causing lsfd to run against a dead process and produce
wrong output.

Exit with EXIT_ENOSYS (23) instead of EXIT_FAILURE when the
multiplexer syscall returns ENOSYS. This applies to both
DEFUN_WAIT_EVENT_SELECT and DEFUN_WAIT_EVENT_POLL macros.

In the bash test, check the wait exit code for 23 after the coproc
finishes and skip the subtest cleanly.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/tests/helpers/test_mkfds.c b/tests/helpers/test_mkfds.c
index 746174e80..302c3d33c 100644
--- a/tests/helpers/test_mkfds.c
+++ b/tests/helpers/test_mkfds.c
@@ -78,7 +78,7 @@
 #define EXIT_EPROTONOSUPPORT 20
 #define EXIT_EACCES 21
 #define EXIT_ENOENT 22
-#define EXIT_ENOSYS 23
+/* EXIT_ENOSYS also defined in test_mkfds.h */
 #define EXIT_EADDRNOTAVAIL 24
 #define EXIT_ENODEV 25
 
@@ -4551,8 +4551,11 @@ static void sighandler_nop(int si _U_)
 		SETUP_SIG_HANDLER					\
 									\
 		if (SYSCALL_INVOCATION < 0				\
-		    && errno != EINTR)					\
+		    && errno != EINTR) {				\
+			if (errno == ENOSYS)				\
+				errx(EXIT_ENOSYS, "no syscall: " SYSCALL); \
 			err(EXIT_FAILURE, "failed in " SYSCALL);	\
+		}							\
 	}
 
 DEFUN_WAIT_EVENT_SELECT(default,
diff --git a/tests/helpers/test_mkfds.h b/tests/helpers/test_mkfds.h
index 1002ee19d..e7a1f06e5 100644
--- a/tests/helpers/test_mkfds.h
+++ b/tests/helpers/test_mkfds.h
@@ -23,6 +23,8 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#define EXIT_ENOSYS 23
+
 enum multiplexing_mode {
    MX_READ   = 1 << 0,
    MX_WRITE  = 1 << 1,
@@ -72,8 +74,11 @@ struct fdesc {
 		SETUP_SIG_HANDLER					\
 									\
 		if (SYSCALL_INVOCATION < 0				\
-		    && errno != EINTR)					\
+		    && errno != EINTR) {				\
+			if (errno == ENOSYS)				\
+				errx(EXIT_ENOSYS, "no syscall: " SYSCALL); \
 			err(EXIT_FAILURE, "failed in " SYSCALL);	\
+		}							\
 		free(pfds);						\
 	}
 
diff --git a/tests/ts/lsfd/mkfds-multiplexing b/tests/ts/lsfd/mkfds-multiplexing
index fdb175f8a..79f4d5530 100755
--- a/tests/ts/lsfd/mkfds-multiplexing
+++ b/tests/ts/lsfd/mkfds-multiplexing
@@ -89,6 +89,9 @@ for multiplexer in pselect6 select poll ppoll; do
     fi
 
     wait "$MKFDS_CPID"
+    if [ $? -eq 23 ]; then
+	ts_skip "the $multiplexer syscall is not available (ENOSYS)"
+    fi
     ts_finalize_subtest
 done