[PATCH v2 1/1] i3c: fix refcount inconsistency in i3c_master_register

[PATCH v2 1/1] i3c: fix refcount inconsistency in i3c_master_register

[Frank Li]

In `i3c_master_register`, a possible refcount inconsistency has been
identified, causing possible resource leak.

Function `of_node_get` increases the refcount of `parent->of_node`. If
function `i3c_bus_init` fails, the function returns immediately without
a corresponding decrease, resulting in an inconsistent refcounter.

Move call i3c_bus_init() after device_initialize() to let callback
i3c_masterdev_release() release of_node.

Reported-by: Shuhao Fu <sfual@cse.ust.hk>
Closes: https://lore.kernel.org/linux-i3c/aO2tjp_FsV_WohPG@osx.local/T/#m2c05a982beeb14e7bf039c1d8db856734bf234c7
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change in v2:
use i3c_masterdev_release() to put of_node to align other error path

v1 by Shuhao Fu <sfual@cse.ust.hk>

https://lore.kernel.org/linux-i3c/aO2tjp_FsV_WohPG@osx.local/T/#m2c05a982beeb14e7bf039c1d8db856734bf234c7
---
 drivers/i3c/master.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index f5f44bd4f4839..b36d4ffadeff2 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2814,10 +2814,6 @@ int i3c_master_register(struct i3c_master_controller *master,
 	INIT_LIST_HEAD(&master->boardinfo.i2c);
 	INIT_LIST_HEAD(&master->boardinfo.i3c);
 
-	ret = i3c_bus_init(i3cbus, master->dev.of_node);
-	if (ret)
-		return ret;
-
 	device_initialize(&master->dev);
 	dev_set_name(&master->dev, "i3c-%d", i3cbus->id);
 
@@ -2825,6 +2821,10 @@ int i3c_master_register(struct i3c_master_controller *master,
 	master->dev.coherent_dma_mask = parent->coherent_dma_mask;
 	master->dev.dma_parms = parent->dma_parms;
 
+	ret = i3c_bus_init(i3cbus, master->dev.of_node);
+	if (ret)
+		goto err_put_dev;
+
 	ret = of_populate_i3c_bus(master);
 	if (ret)
 		goto err_put_dev;
-- 
2.34.1


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Re: [PATCH v2 1/1] i3c: fix refcount inconsistency in i3c_master_register

[Markus Elfring]

> In `i3c_master_register`, a possible refcount inconsistency has been
> identified, causing possible resource leak.
…

How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?

Regards,
Markus

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