remoteproc: Fix potential race condition in rproc_add

rproc_add adds the newly created remoteproc to a list for use by
rproc_get_by_phandle and then does some additional processing to finish
adding the remoteproc. This leaves a small window of time in which the
rproc is available in the list but not yet fully initialized, so if
another driver comes along and gets a handle to the rproc, it will be
invalid. Rearrange the code in rproc_add to make sure the rproc is added
to the list only after it has been successfuly initialized.

Fixes: fec47d863587 ("remoteproc: introduce rproc_get_by_phandle API")
Cc: stable@vger.kernel.org
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index db3958b3f09454c662fdbdcb4b3592d2f8cd9cb3..fe0539ed9cb5911e105732ef68d226499fa9ffb9 100644 (file)
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1264,11 +1264,6 @@ int rproc_add(struct rproc *rproc)
        if (ret < 0)
                return ret;
 
-       /* expose to rproc_get_by_phandle users */
-       mutex_lock(&rproc_list_mutex);
-       list_add(&rproc->node, &rproc_list);
-       mutex_unlock(&rproc_list_mutex);
-
        dev_info(dev, "%s is available\n", rproc->name);
 
        dev_info(dev, "Note: remoteproc is still under development and considered experimental.\n");
@@ -1276,8 +1271,16 @@ int rproc_add(struct rproc *rproc)
 
        /* create debugfs entries */
        rproc_create_debug_dir(rproc);
+       ret = rproc_add_virtio_devices(rproc);
+       if (ret < 0)
+               return ret;
 
-       return rproc_add_virtio_devices(rproc);
+       /* expose to rproc_get_by_phandle users */
+       mutex_lock(&rproc_list_mutex);
+       list_add(&rproc->node, &rproc_list);
+       mutex_unlock(&rproc_list_mutex);
+
+       return 0;
 }
 EXPORT_SYMBOL(rproc_add);