rpmsg: Fix calling device_lock() on non-initialized device

driver_set_override() helper uses device_lock() so it should not be
called before rpmsg_register_device() (which calls device_register()).
Effect can be seen with CONFIG_DEBUG_MUTEXES:

  DEBUG_LOCKS_WARN_ON(lock->magic != lock)
  WARNING: CPU: 3 PID: 57 at kernel/locking/mutex.c:582 __mutex_lock+0x1ec/0x430
  ...
  Call trace:
   __mutex_lock+0x1ec/0x430
   mutex_lock_nested+0x44/0x50
   driver_set_override+0x124/0x150
   qcom_glink_native_probe+0x30c/0x3b0
   glink_rpm_probe+0x274/0x350
   platform_probe+0x6c/0xe0
   really_probe+0x17c/0x3d0
   __driver_probe_device+0x114/0x190
   driver_probe_device+0x3c/0xf0
   ...

Refactor the rpmsg_register_device() function to use two-step device
registering (initialization + add) and call driver_set_override() in
proper moment.

This moves the code around, so while at it also NULL-ify the
rpdev->driver_override in error path to be sure it won't be kfree()
second time.

Fixes: 42cd402b8fd4 ("rpmsg: Fix kfree() of static memory on setting driver_override")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220429195946.1061725-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 95fc283..4938fc4 100644 (file)
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -593,24 +593,51 @@ static struct bus_type rpmsg_bus = {
        .remove         = rpmsg_dev_remove,
 };
 
-int rpmsg_register_device(struct rpmsg_device *rpdev)
+/*
+ * A helper for registering rpmsg device with driver override and name.
+ * Drivers should not be using it, but instead rpmsg_register_device().
+ */
+int rpmsg_register_device_override(struct rpmsg_device *rpdev,
+                                  const char *driver_override)
 {
        struct device *dev = &rpdev->dev;
        int ret;
 
+       if (driver_override)
+               strcpy(rpdev->id.name, driver_override);
+
        dev_set_name(&rpdev->dev, "%s.%s.%d.%d", dev_name(dev->parent),
                     rpdev->id.name, rpdev->src, rpdev->dst);
 
        rpdev->dev.bus = &rpmsg_bus;
 
-       ret = device_register(&rpdev->dev);
+       device_initialize(dev);
+       if (driver_override) {
+               ret = driver_set_override(dev, &rpdev->driver_override,
+                                         driver_override,
+                                         strlen(driver_override));
+               if (ret) {
+                       dev_err(dev, "device_set_override failed: %d\n", ret);
+                       return ret;
+               }
+       }
+
+       ret = device_add(dev);
        if (ret) {
-               dev_err(dev, "device_register failed: %d\n", ret);
+               dev_err(dev, "device_add failed: %d\n", ret);
+               kfree(rpdev->driver_override);
+               rpdev->driver_override = NULL;
                put_device(&rpdev->dev);
        }
 
        return ret;
 }
+EXPORT_SYMBOL(rpmsg_register_device_override);
+
+int rpmsg_register_device(struct rpmsg_device *rpdev)
+{
+       return rpmsg_register_device_override(rpdev, NULL);
+}
 EXPORT_SYMBOL(rpmsg_register_device);
 
 /*

diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 3e81642..a22cd4a 100644 (file)
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -94,19 +94,7 @@ int rpmsg_release_channel(struct rpmsg_device *rpdev,
  */
 static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev)
 {
-       int ret;
-
-       strcpy(rpdev->id.name, "rpmsg_ctrl");
-       ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
-                                 rpdev->id.name, strlen(rpdev->id.name));
-       if (ret)
-               return ret;
-
-       ret = rpmsg_register_device(rpdev);
-       if (ret)
-               kfree(rpdev->driver_override);
-
-       return ret;
+       return rpmsg_register_device_override(rpdev, "rpmsg_ctrl");
 }
 
 #endif

diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
index 8eb8f32..c70ad03 100644 (file)
--- a/drivers/rpmsg/rpmsg_ns.c
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -20,22 +20,10 @@
  */
 int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
 {
-       int ret;
-
-       strcpy(rpdev->id.name, "rpmsg_ns");
-       ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
-                                 rpdev->id.name, strlen(rpdev->id.name));
-       if (ret)
-               return ret;
-
        rpdev->src = RPMSG_NS_ADDR;
        rpdev->dst = RPMSG_NS_ADDR;
 
-       ret = rpmsg_register_device(rpdev);
-       if (ret)
-               kfree(rpdev->driver_override);
-
-       return ret;
+       return rpmsg_register_device_override(rpdev, "rpmsg_ns");
 }
 EXPORT_SYMBOL(rpmsg_ns_register_device);
 

diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 20c8cd1..523c98b 100644 (file)
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -165,6 +165,8 @@ static inline __rpmsg64 cpu_to_rpmsg64(struct rpmsg_device *rpdev, u64 val)
 
 #if IS_ENABLED(CONFIG_RPMSG)
 
+int rpmsg_register_device_override(struct rpmsg_device *rpdev,
+                                  const char *driver_override);
 int rpmsg_register_device(struct rpmsg_device *rpdev);
 int rpmsg_unregister_device(struct device *parent,
                            struct rpmsg_channel_info *chinfo);
@@ -192,6 +194,12 @@ ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
 
 #else
 
+static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev,
+                                                const char *driver_override)
+{
+       return -ENXIO;
+}
+
 static inline int rpmsg_register_device(struct rpmsg_device *rpdev)
 {
        return -ENXIO;