Re: [Qemu-devel] help debugging throttle crash

[Alberto Garcia <berto@igalia.com>]

On Mon, Apr 03, 2017 at 09:07:02AM -0500, Eric Blake wrote:

> At this point, it looks like no one is calling
> throttle_group_unregister_blk() as a result of the 'device_del',
> which leaves stale memory around

I see, I can also reproduce this very easily.

I wonder if it's not enough to simply disable I/O limits when a
BlockBackend is deleted?

--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -230,6 +230,9 @@ static void blk_delete(BlockBackend *blk)
     assert(!blk->refcnt);
     assert(!blk->name);
     assert(!blk->dev);
+    if (blk->public.throttle_state) {
+        blk_io_limits_disable(blk);
+    }
     if (blk->root) {
         blk_remove_bs(blk);
     }

Berto