This is a note to let you know that I've just added the patch titled
platform/x86: lenovo-yoga-tab2-pro-1380-fastcharger: fix serdev race
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
platform-x86-lenovo-yoga-tab2-pro-1380-fastcharger-f.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 12834b0c4f900d665235a6cfd15e1b8a6b6b058d
Author: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
Date: Sat Jan 11 12:09:51 2025 -0600
platform/x86: lenovo-yoga-tab2-pro-1380-fastcharger: fix serdev race
[ Upstream commit 59616a91e5e74833b2008b56c66879857c616006 ]
The yt2_1380_fc_serdev_probe() function calls devm_serdev_device_open()
before setting the client ops via serdev_device_set_client_ops(). This
ordering can trigger a NULL pointer dereference in the serdev controller's
receive_buf handler, as it assumes serdev->ops is valid when
SERPORT_ACTIVE is set.
This is similar to the issue fixed in commit 5e700b384ec1
("platform/chrome: cros_ec_uart: properly fix race condition") where
devm_serdev_device_open() was called before fully initializing the
device.
Fix the race by ensuring client ops are set before enabling the port via
devm_serdev_device_open().
Note, serdev_device_set_baudrate() and serdev_device_set_flow_control()
calls should be after the devm_serdev_device_open() call.
Fixes: b2ed33e8d486 ("platform/x86: Add lenovo-yoga-tab2-pro-1380-fastcharger driver")
Signed-off-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250111180951.2277757-1-chenyuan0y@xxxxxxxxx
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c b/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c
index d525bdc8ca9b3..32d9b6009c422 100644
--- a/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c
+++ b/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c
@@ -199,14 +199,15 @@ static int yt2_1380_fc_serdev_probe(struct serdev_device *serdev)
if (ret)
return ret;
+ serdev_device_set_drvdata(serdev, fc);
+ serdev_device_set_client_ops(serdev, &yt2_1380_fc_serdev_ops);
+
ret = devm_serdev_device_open(dev, serdev);
if (ret)
return dev_err_probe(dev, ret, "opening UART device\n");
serdev_device_set_baudrate(serdev, 600);
serdev_device_set_flow_control(serdev, false);
- serdev_device_set_drvdata(serdev, fc);
- serdev_device_set_client_ops(serdev, &yt2_1380_fc_serdev_ops);
ret = devm_extcon_register_notifier_all(dev, fc->extcon, &fc->nb);
if (ret)
