Re: [Qemu-devel] [PATCH 1/2] nbd/server: add additional assert to nbd_export_put

[Max Reitz]

On 2017-11-09 16:40, Vladimir Sementsov-Ogievskiy wrote:
> This place is not obvious, nbd_export_close may theoretically reduce
> refcount to 0. It may happen if someone calls nbd_export_put on named
> export not through nbd_export_set_name when refcount is 1.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy 
> ---
>  nbd/server.c | 1 +
>  1 file changed, 1 insertion(+)
Reviewed-by: Max Reitz 



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[Qemu-devel] [PATCH 1/2] nbd/server: add additional assert to nbd_export_put

[Vladimir Sementsov-Ogievskiy]

This place is not obvious, nbd_export_close may theoretically reduce
refcount to 0. It may happen if someone calls nbd_export_put on named
export not through nbd_export_set_name when refcount is 1.

Signed-off-by: Vladimir Sementsov-Ogievskiy 
---
 nbd/server.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nbd/server.c b/nbd/server.c
index 70b40ed27e..2f2e05943f 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1179,6 +1179,7 @@ void nbd_export_put(NBDExport *exp)
 nbd_export_close(exp);
 }
 
+assert(exp->refcount > 0);
 if (--exp->refcount == 0) {
 assert(exp->name == NULL);
 assert(exp->description == NULL);
-- 
2.11.1