dm: core: Fix code reentrancy issue in device_probe_child()

The device might have already been probed during the call to
device_probe() on its parent device (e.g. PCI bridge devices).
In its parent device's probe routine, it might probe all of
its child devices via device_probe() thus the codes reenter
device_probe_child(). To support code reentrancy, test these
allocated memory against NULL to avoid memory leak, and return
to the caller if dev->flags has DM_FLAG_ACTIVATED set after
device_probe() returns, so that we don't mess up the device.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/core/device.c b/drivers/core/device.c
index e23a8725e7ab06d96fbf617a083dcefaa16e980a..a31e25f6b5c5b30b92c2d0251c5dd083f3939de2 100644 (file)
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -226,17 +226,17 @@ int device_probe_child(struct udevice *dev, void *parent_priv)
        drv = dev->driver;
        assert(drv);
 
-       /* Allocate private data if requested */
-       if (drv->priv_auto_alloc_size) {
+       /* Allocate private data if requested and not reentered */
+       if (drv->priv_auto_alloc_size && !dev->priv) {
                dev->priv = alloc_priv(drv->priv_auto_alloc_size, drv->flags);
                if (!dev->priv) {
                        ret = -ENOMEM;
                        goto fail;
                }
        }
-       /* Allocate private data if requested */
+       /* Allocate private data if requested and not reentered */
        size = dev->uclass->uc_drv->per_device_auto_alloc_size;
-       if (size) {
+       if (size && !dev->uclass_priv) {
                dev->uclass_priv = calloc(1, size);
                if (!dev->uclass_priv) {
                        ret = -ENOMEM;
@@ -251,7 +251,7 @@ int device_probe_child(struct udevice *dev, void *parent_priv)
                        size = dev->parent->uclass->uc_drv->
                                        per_child_auto_alloc_size;
                }
-               if (size) {
+               if (size && !dev->parent_priv) {
                        dev->parent_priv = alloc_priv(size, drv->flags);
                        if (!dev->parent_priv) {
                                ret = -ENOMEM;
@@ -264,6 +264,15 @@ int device_probe_child(struct udevice *dev, void *parent_priv)
                ret = device_probe(dev->parent);
                if (ret)
                        goto fail;
+
+               /*
+                * The device might have already been probed during
+                * the call to device_probe() on its parent device
+                * (e.g. PCI bridge devices). Test the flags again
+                * so that we don't mess up the device.
+                */
+               if (dev->flags & DM_FLAG_ACTIVATED)
+                       return 0;
        }
 
        seq = uclass_resolve_seq(dev);