[Qemu-stable] [PATCH stable-0.15 06/36] compatfd.c: Don't pass NULL pointer to SYS_signalfd

[Andreas Färber]

From: Peter Maydell <address@hidden>

Don't pass a NULL pointer in to SYS_signalfd in qemu_signalfd_available():
this isn't valid and Valgrind complains about it.

Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Andrzej Zaborowski <address@hidden>
(cherry picked from commit 7f84c1272b601be88daeb828ec1890890c7aae25)

Signed-off-by: Bruce Rogers <address@hidden>
Signed-off-by: Andreas Färber <address@hidden>
---
 compatfd.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/compatfd.c b/compatfd.c
index 31654c6..02306a4 100644
--- a/compatfd.c
+++ b/compatfd.c
@@ -119,9 +119,17 @@ int qemu_signalfd(const sigset_t *mask)
 bool qemu_signalfd_available(void)
 {
 #ifdef CONFIG_SIGNALFD
+    sigset_t mask;
+    int fd;
+    bool ok;
+    sigemptyset(&mask);
     errno = 0;
-    syscall(SYS_signalfd, -1, NULL, _NSIG / 8);
-    return errno != ENOSYS;
+    fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
+    ok = (errno != ENOSYS);
+    if (fd >= 0) {
+        close(fd);
+    }
+    return ok;
 #else
     return false;
 #endif
-- 
1.7.7