vl: fix tracing initialization

we should call trace_init_backends() before trace_init_file() for
CONFIG_TRACE_SIMPLE There is no difference for other cases.

This problem was introduced by the commit
    commit 41fc57e44ed64cd4ab5393d83624afd897dabd4f
    Author: Paolo Bonzini <pbonzini@redhat.com>
    Date:   Thu Jan 7 16:55:24 2016 +0300

    trace: split trace_init_file out of trace_init_backends

'make check' was failed as a result if configured with
  --enable-trace-backends=simple

Spotted by Alex Bennée.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1455036545-14870-1-git-send-email-den@openvz.org
CC: Alex Bennée <alex.bennee@linaro.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/vl.c b/vl.c
index 6fea089..f146bc5 100644
--- a/vl.c
+++ b/vl.c
@@ -4081,6 +4081,9 @@ int main(int argc, char **argv, char **envp)
         exit(0);
     }
 
+    if (!trace_init_backends()) {
+        exit(1);
+    }
     trace_init_file(trace_file);
 
     /* Open the logfile at this point and set the log mask if necessary.
@@ -4101,10 +4104,6 @@ int main(int argc, char **argv, char **envp)
         qemu_set_log(0);
     }
 
-    if (!trace_init_backends()) {
-        exit(1);
-    }
-
     /* If no data_dir is specified then try to find it relative to the
        executable path.  */
     if (data_dir_idx < ARRAY_SIZE(data_dir)) {