[PATCH 23/64] vl: Fix an assert failure in error path

[Michael Roth]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

Based on the description of error_setg(), the local variable err in
qemu_maybe_daemonize() should be initialized to NULL.

Without fix, the uninitialized *errp triggers assert failure which
doesn't show much valuable information.

Before the fix:
qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' 
failed.

After fix:
qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission 
denied

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20210610084741.456260-1-zhenzhong.duan@intel.com>
Cc: qemu-stable@nongnu.org
Fixes: 0546c0609c ("vl: split various early command line options to a separate 
function", 2020-12-10)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 38f71349c7c4969bc14da4da1c70b8cc4078d596)
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 softmmu/vl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 6be510b035..848b98851c 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2508,7 +2508,7 @@ static void qemu_process_help_options(void)
 
 static void qemu_maybe_daemonize(const char *pid_file)
 {
-    Error *err;
+    Error *err = NULL;
 
     os_daemonize();
     rcu_disable_atfork();
-- 
2.25.1