From b93008d1ac657dc67819330c5995e65e7c3e7978 Mon Sep 17 00:00:00 2001 From: Simon Gaiser Date: Thu, 15 Mar 2018 03:43:21 +0100 Subject: [PATCH 2/3] xen: xenbus: Catch closing of non existent transactions Users of the xenbus functions should never close a non existent transaction (for example by trying to closing the same transaction twice) but better catch it in xs_request_exit() than to corrupt the reference counter. Signed-off-by: Simon Gaiser Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky --- drivers/xen/xenbus/xenbus_xs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index 3f3b29398ab8..49a3874ae6bb 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -140,7 +140,9 @@ void xs_request_exit(struct xb_req_data *req) spin_lock(&xs_state_lock); xs_state_users--; if ((req->type == XS_TRANSACTION_START && req->msg.type == XS_ERROR) || - req->type == XS_TRANSACTION_END) + (req->type == XS_TRANSACTION_END && + !WARN_ON_ONCE(req->msg.type == XS_ERROR && + !strcmp(req->body, "ENOENT")))) xs_state_users--; spin_unlock(&xs_state_lock); -- 2.16.2