From mboxrd@z Thu Jan 1 00:00:00 1970 From: logang@deltatee.com (Logan Gunthorpe) Date: Wed, 31 Jul 2019 17:35:32 -0600 Subject: [PATCH v3 2/4] nvmet-loop: Flush nvme_delete_wq when removing the port In-Reply-To: <20190731233534.4841-1-logang@deltatee.com> References: <20190731233534.4841-1-logang@deltatee.com> Message-ID: <20190731233534.4841-3-logang@deltatee.com> After calling nvme_loop_delete_ctrl(), the controllers will not yet be deleted because nvme_delete_ctrl() only schedules work to do the delete. This means a race can occur if a port is removed but there are still active controllers trying to access that memory. To fix this, flush the nvme_delete_wq before returning from nvme_loop_remove_port() so that any controllers that might be in the process of being deleted won't access a freed port. Signed-off-by: Logan Gunthorpe Reviewed-by: Sagi Grimberg Reviewed-by: Max Gurtovoy --- drivers/nvme/target/loop.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c index b16dc3981c69..0940c5024a34 100644 --- a/drivers/nvme/target/loop.c +++ b/drivers/nvme/target/loop.c @@ -654,6 +654,14 @@ static void nvme_loop_remove_port(struct nvmet_port *port) mutex_lock(&nvme_loop_ports_mutex); list_del_init(&port->entry); mutex_unlock(&nvme_loop_ports_mutex); + + /* + * Ensure any ctrls that are in the process of being + * deleted are in fact deleted before we return + * and free the port. This is to prevent active + * ctrls from using a port after it's freed. + */ + flush_workqueue(nvme_delete_wq); } static const struct nvmet_fabrics_ops nvme_loop_ops = { -- 2.20.1