[PATCH v2 1/4] selftests/futex: Let futex_waitv() take no timeout

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

The futex_waitv() helper of futex2test.h copies the caller's timeout
into a struct __kernel_timespec. It dereferences the pointer without a
check, so a caller cannot pass NULL. The syscall takes NULL as no
timeout.

Pass NULL to the syscall when the caller passes NULL. The futex_waitv
tests use this in a later patch, to wait until they are woken.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 tools/testing/selftests/futex/include/futex2test.h | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/futex/include/futex2test.h b/tools/testing/selftests/futex/include/futex2test.h
index 53e88b60ac6d..a4616b6edcff 100644
--- a/tools/testing/selftests/futex/include/futex2test.h
+++ b/tools/testing/selftests/futex/include/futex2test.h
@@ -68,12 +68,16 @@ struct futex32_numa {
 static inline int futex_waitv(volatile struct futex_waitv *waiters, unsigned long nr_waiters,
 			      unsigned long flags, struct timespec *timo, clockid_t clockid)
 {
-		struct __kernel_timespec ts = {
-			.tv_sec = timo->tv_sec,
-			.tv_nsec = timo->tv_nsec,
-		};
+		struct __kernel_timespec ts, *tsp = NULL;
 
-		return syscall(__NR_futex_waitv, waiters, nr_waiters, flags, &ts, clockid);
+		/* No timeout: wait until woken. */
+		if (timo) {
+			ts.tv_sec = timo->tv_sec;
+			ts.tv_nsec = timo->tv_nsec;
+			tsp = &ts;
+		}
+
+		return syscall(__NR_futex_waitv, waiters, nr_waiters, flags, tsp, clockid);
 }
 
 /*
-- 
2.47.3