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    Subject[PATCH v3 2/4] nvmet-loop: Flush nvme_delete_wq when removing the port
    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 <logang@deltatee.com>
    Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
    Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
    ---
    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
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