Revert "spi: fix use-after-free of the add_lock mutex" [5.4.286]

This reverts commit 54c2c96eafcfd242e52e932ab54ace4784efe1dd which is commit 6c53b45c71b4920b5e62f0ea8079a1da382b9434 upstream. It breaks the Android kernel abi and can be brought back in the future in an abi-safe way if it is really needed. Bug: 161946584 Change-Id: Icce07d26ecdbeb799b479babd47730046b402902 Signed-off-by: Greg Kroah-Hartman <[email protected]>
psndna88 · Nov 26, 2024 · 6e58fa8 · 6e58fa8
1 parent c27c16f
commit 6e58fa8
Showing 1 changed file with 8 additions and 8 deletions.
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
@@ -2674,21 +2674,21 @@ void spi_unregister_controller(struct spi_controller *ctlr)
 
 	device_del(&ctlr->dev);
 
+	/* Release the last reference on the controller if its driver
+	 * has not yet been converted to devm_spi_alloc_master/slave().
+	 */
+	if (!devres_find(ctlr->dev.parent, devm_spi_release_controller,
+			 devm_spi_match_controller, ctlr))
+		put_device(&ctlr->dev);
+
 	/* free bus id */
 	mutex_lock(&board_lock);
 	if (found == ctlr)
 		idr_remove(&spi_master_idr, id);
 	mutex_unlock(&board_lock);
 
 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
-		mutex_unlock(&ctlr->add_lock);
-
-	/* Release the last reference on the controller if its driver
-	 * has not yet been converted to devm_spi_alloc_master/slave().
-	 */
-	if (!devres_find(ctlr->dev.parent, devm_spi_release_controller,
-			 devm_spi_match_controller, ctlr))
-		put_device(&ctlr->dev);
+		mutex_unlock(&spi_add_lock);
 }
 EXPORT_SYMBOL_GPL(spi_unregister_controller);