[PATCH v2] tools/virtio: check mmap return value in vringh_test

[longlong yan <yanlonglong@kylinos.cn>]

In parallel_test(), the return values of mmap() for both host_map and
guest_map are not checked against MAP_FAILED. If mmap() fails, the
subsequent code will dereference the invalid pointer, leading to a
segmentation fault.

Add MAP_FAILED checks after both mmap() calls, using err() to report
the error and exit, consistent with the existing error handling style
in this file (e.g., the open() call on line 149).

Fixes: 1515c5ce26ae("tools/virtio: add vring_test.")
Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
---
 tools/virtio/vringh_test.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/virtio/vringh_test.c b/tools/virtio/vringh_test.c
index b9591223437a..5ea6d29bc992 100644
--- a/tools/virtio/vringh_test.c
+++ b/tools/virtio/vringh_test.c
@@ -159,7 +159,12 @@ static int parallel_test(u64 features,
 
 	/* Parent and child use separate addresses, to check our mapping logic! */
 	host_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (host_map == MAP_FAILED)
+		err(1, "mmap host_map");
+
 	guest_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (guest_map == MAP_FAILED)
+		err(1, "mmap guest_map");
 
 	pipe_ret = pipe(to_guest);
 	assert(!pipe_ret);
-- 
2.43.0