Add the function of colo_compare_cleanup

This patch fixes the following:
    #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
    #1  0x00007f6ae4559859 in __GI_abort () at abort.c:79
    #2  0x0000559aaa386720 in error_exit (err=16, msg=0x559aaa5973d0 <__func__.16227> "qemu_mutex_destroy") at util/qemu-thread-posix.c:36
    #3  0x0000559aaa3868c5 in qemu_mutex_destroy (mutex=0x559aabffe828) at util/qemu-thread-posix.c:69
    #4  0x0000559aaa2f93a8 in char_finalize (obj=0x559aabffe800) at chardev/char.c:285
    #5  0x0000559aaa23318a in object_deinit (obj=0x559aabffe800, type=0x559aabfd7d20) at qom/object.c:606
    #6  0x0000559aaa2331b8 in object_deinit (obj=0x559aabffe800, type=0x559aabfd9060) at qom/object.c:610
    #7  0x0000559aaa233200 in object_finalize (data=0x559aabffe800) at qom/object.c:620
    #8  0x0000559aaa234202 in object_unref (obj=0x559aabffe800) at qom/object.c:1074
    #9  0x0000559aaa2356b6 in object_finalize_child_property (obj=0x559aac0dac10, name=0x559aac778760 "compare0-0", opaque=0x559aabffe800) at qom/object.c:1584
    #10 0x0000559aaa232f70 in object_property_del_all (obj=0x559aac0dac10) at qom/object.c:557
    #11 0x0000559aaa2331ed in object_finalize (data=0x559aac0dac10) at qom/object.c:619
    #12 0x0000559aaa234202 in object_unref (obj=0x559aac0dac10) at qom/object.c:1074
    #13 0x0000559aaa2356b6 in object_finalize_child_property (obj=0x559aac0c75c0, name=0x559aac0dadc0 "chardevs", opaque=0x559aac0dac10) at qom/object.c:1584
    #14 0x0000559aaa233071 in object_property_del_child (obj=0x559aac0c75c0, child=0x559aac0dac10, errp=0x0) at qom/object.c:580
    #15 0x0000559aaa233155 in object_unparent (obj=0x559aac0dac10) at qom/object.c:599
    #16 0x0000559aaa2fb721 in qemu_chr_cleanup () at chardev/char.c:1159
    #17 0x0000559aa9f9b110 in main (argc=54, argv=0x7ffeb62fa998, envp=0x7ffeb62fab50) at vl.c:4539

When chardev is cleaned up, chr_write_lock needs to be destroyed. But
the colo-compare module is not cleaned up normally before it when the
guest poweroff. It is holding chr_write_lock at this time. This will
cause qemu crash.So we add the function of colo_compare_cleanup() before
qemu_chr_cleanup() to fix the bug.

Signed-off-by: Lei Rao <[email protected]>
Reviewed-by: Zhang Chen <[email protected]>
Reviewed-by: Lukas Straub <[email protected]>
Tested-by: Lukas Straub <[email protected]>
Signed-off-by: Zhang Chen <[email protected]>
Signed-off-by: Jason Wang <[email protected]>

net/colo-compare.c

@@ -1402,6 +1402,16 @@ static void colo_compare_init(Object *obj)
                              compare_set_vnet_hdr);
 }
 
+void colo_compare_cleanup(void)
+{
+    CompareState *tmp = NULL;
+    CompareState *n = NULL;
+
+    QTAILQ_FOREACH_SAFE(tmp, &net_compares, next, n) {
+        object_unparent(OBJECT(tmp));
+    }
+}
+
 static void colo_compare_finalize(Object *obj)
 {
     CompareState *s = COLO_COMPARE(obj);

net/colo-compare.h

@@ -20,5 +20,6 @@
 void colo_notify_compares_event(void *opaque, int event, Error **errp);
 void colo_compare_register_notifier(Notifier *notify);
 void colo_compare_unregister_notifier(Notifier *notify);
+void colo_compare_cleanup(void);
 
 #endif /* QEMU_COLO_COMPARE_H */

net/net.c

@@ -52,6 +52,7 @@
 #include "qapi/error.h"
 #include "qapi/opts-visitor.h"
 #include "sysemu/runstate.h"
+#include "net/colo-compare.h"
 #include "net/filter.h"
 #include "qapi/string-output-visitor.h"
 
@@ -1402,6 +1403,9 @@ void net_cleanup(void)
 {
     NetClientState *nc;
 
+    /*cleanup colo compare module for COLO*/
+    colo_compare_cleanup();
+
     /* We may del multiple entries during qemu_del_net_client(),
      * so QTAILQ_FOREACH_SAFE() is also not safe here.
      */