diff mbox series

[v1,1/2] migration: block-dirty-bitmap: add missing qemu_mutex_lock_iothread

Message ID 20211005080751.3797161-2-eesposit@redhat.com
State New
Headers show
Series Migration: fix missing iothread locking | expand

Commit Message

Emanuele Giuseppe Esposito Oct. 5, 2021, 8:07 a.m. UTC 
init_dirty_bitmap_migration assumes the iothread lock (BQL)
to be held, but instead it isn't.

Instead of adding the lock to qemu_savevm_state_setup(),
follow the same pattern as the other ->save_setup callbacks
and lock+unlock inside dirty_bitmap_save_setup().

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 migration/block-dirty-bitmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Juan Quintela Nov. 2, 2021, 9:11 a.m. UTC | #1 
Emanuele Giuseppe Esposito <eesposit@redhat.com> wrote:
> init_dirty_bitmap_migration assumes the iothread lock (BQL)
> to be held, but instead it isn't.
>
> Instead of adding the lock to qemu_savevm_state_setup(),
> follow the same pattern as the other ->save_setup callbacks
> and lock+unlock inside dirty_bitmap_save_setup().
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

queued.
Juan Quintela Nov. 2, 2021, 9:15 a.m. UTC | #2 
Juan Quintela <quintela@redhat.com> wrote:
> Emanuele Giuseppe Esposito <eesposit@redhat.com> wrote:
>> init_dirty_bitmap_migration assumes the iothread lock (BQL)
>> to be held, but instead it isn't.
>>
>> Instead of adding the lock to qemu_savevm_state_setup(),
>> follow the same pattern as the other ->save_setup callbacks
>> and lock+unlock inside dirty_bitmap_save_setup().
>>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>
> Reviewed-by: Juan Quintela <quintela@redhat.com>

And I realized that this patch is already on the tree, just not through
the migration tree.

Ignore the noise.

Later, Juan.
diff mbox series

Patch

diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index 35f5ef688d..9aba7d9c22 100644
--- a/migration/block-dirty-bitmap.c
+++ b/migration/block-dirty-bitmap.c
@@ -1215,7 +1215,10 @@  static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
 {
     DBMSaveState *s = &((DBMState *)opaque)->save;
     SaveBitmapState *dbms = NULL;
+
+    qemu_mutex_lock_iothread();
     if (init_dirty_bitmap_migration(s) < 0) {
+        qemu_mutex_unlock_iothread();
         return -1;
     }
 
@@ -1223,7 +1226,7 @@  static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
         send_bitmap_start(f, s, dbms);
     }
     qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
-
+    qemu_mutex_unlock_iothread();
     return 0;
 }