[PULL 15/30] migration: Take bitmap mutex when completing ram migration

[Juan Quintela <quintela@redhat.com>]

From: Peter Xu <peterx@redhat.com>

Any call to ram_find_and_save_block() needs to take the bitmap mutex.  We
used to not take it for most of ram_save_complete() because we thought
we're the only one left using the bitmap, but it's not true after the
preempt full patchset applied, since the return path can be taking it too.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/migration/ram.c b/migration/ram.c
index 2fcce796d0..96fa521813 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3434,6 +3434,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
         /* try transferring iterative blocks of memory */
 
         /* flush all remaining blocks regardless of rate limiting */
+        qemu_mutex_lock(&rs->bitmap_mutex);
         while (true) {
             int pages;
 
@@ -3447,6 +3448,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
                 break;
             }
         }
+        qemu_mutex_unlock(&rs->bitmap_mutex);
 
         flush_compressed_data(rs);
         ram_control_after_iterate(f, RAM_CONTROL_FINISH);
-- 
2.38.1