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[Qemu-devel] [PULL 1/2] nbd/server: add additional assert to nbd_export_
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 1/2] nbd/server: add additional assert to nbd_export_put |
Date: |
Wed, 10 Jan 2018 16:59:43 -0600 |
From: Vladimir Sementsov-Ogievskiy <address@hidden>
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 <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Eric Blake <address@hidden>
---
nbd/server.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/nbd/server.c b/nbd/server.c
index e443b3cf5c..6cf2eeb2c1 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1190,6 +1190,12 @@ void nbd_export_put(NBDExport *exp)
nbd_export_close(exp);
}
+ /* 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. So, let's assert that
+ * it is > 0.
+ */
+ assert(exp->refcount > 0);
if (--exp->refcount == 0) {
assert(exp->name == NULL);
assert(exp->description == NULL);
--
2.14.3