Valgrind complains about the probe_o_direct_support() function reading
from an uninitialized buffer. For probing O_DIRECT support we don't
actually need to write to the file, just make sure the pwrite call
doesn't reject the write. Still, write zeroes to the buffer to
suppress the warning.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20241209204427.17763-3-farosas@suse.de>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 tests/qtest/migration/migration-util.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/qtest/migration/migration-util.c b/tests/qtest/migration/migration-util.c
index 525bf1eed4..401fe27f00 100644
--- a/tests/qtest/migration/migration-util.c
+++ b/tests/qtest/migration/migration-util.c
@@ -284,6 +284,7 @@ bool probe_o_direct_support(const char *tmpfs)
 
     buf = qemu_try_memalign(len, len);
     g_assert(buf);
+    memset(buf, 0, len);
 
     ret = pwrite(fd, buf, len, offset);
     unlink(filename);
-- 
2.35.3