The cros_ec_device can be unregistered when the underlying device is removed. Other kernel drivers that interact with the EC may hold a pointer to the cros_ec_device, creating a risk of a use-after-free error if the EC device is removed while still being referenced. To prevent this, leverage the revocable and convert the underlying device drivers to resource providers of cros_ec_device. Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx> --- v2: - Rename "ref_proxy" -> "revocable". v1: https://lore.kernel.org/chrome-platform/20250814091020.1302888-3-tzungbi@xxxxxxxxxx drivers/platform/chrome/cros_ec_i2c.c | 5 +++++ drivers/platform/chrome/cros_ec_ishtp.c | 5 +++++ drivers/platform/chrome/cros_ec_lpc.c | 5 +++++ drivers/platform/chrome/cros_ec_rpmsg.c | 5 +++++ drivers/platform/chrome/cros_ec_spi.c | 4 ++++ drivers/platform/chrome/cros_ec_uart.c | 5 +++++ include/linux/platform_data/cros_ec_proto.h | 4 ++++ 7 files changed, 33 insertions(+) diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c index 38af97cdaab2..68a8d2c65ca3 100644 --- a/drivers/platform/chrome/cros_ec_i2c.c +++ b/drivers/platform/chrome/cros_ec_i2c.c @@ -12,6 +12,7 @@ #include <linux/platform_data/cros_ec_commands.h> #include <linux/platform_data/cros_ec_proto.h> #include <linux/platform_device.h> +#include <linux/revocable.h> #include <linux/slab.h> #include "cros_ec.h" @@ -296,6 +297,10 @@ static int cros_ec_i2c_probe(struct i2c_client *client) if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; + i2c_set_clientdata(client, ec_dev); ec_dev->dev = dev; ec_dev->priv = client; diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c index 7e7190b30cbb..3467b4e9ceb5 100644 --- a/drivers/platform/chrome/cros_ec_ishtp.c +++ b/drivers/platform/chrome/cros_ec_ishtp.c @@ -12,6 +12,7 @@ #include <linux/pci.h> #include <linux/platform_data/cros_ec_commands.h> #include <linux/platform_data/cros_ec_proto.h> +#include <linux/revocable.h> #include <linux/intel-ish-client-if.h> #include "cros_ec.h" @@ -547,6 +548,10 @@ static int cros_ec_dev_init(struct ishtp_cl_data *client_data) if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; + client_data->ec_dev = ec_dev; dev->driver_data = ec_dev; diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c index 7d9a78289c96..77bdaf430979 100644 --- a/drivers/platform/chrome/cros_ec_lpc.c +++ b/drivers/platform/chrome/cros_ec_lpc.c @@ -23,6 +23,7 @@ #include <linux/platform_device.h> #include <linux/printk.h> #include <linux/reboot.h> +#include <linux/revocable.h> #include <linux/suspend.h> #include "cros_ec.h" @@ -641,6 +642,10 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; + platform_set_drvdata(pdev, ec_dev); ec_dev->dev = dev; ec_dev->phys_name = dev_name(dev); diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c index bc2666491db1..04d886829aa7 100644 --- a/drivers/platform/chrome/cros_ec_rpmsg.c +++ b/drivers/platform/chrome/cros_ec_rpmsg.c @@ -10,6 +10,7 @@ #include <linux/platform_data/cros_ec_commands.h> #include <linux/platform_data/cros_ec_proto.h> #include <linux/platform_device.h> +#include <linux/revocable.h> #include <linux/rpmsg.h> #include <linux/slab.h> @@ -220,6 +221,10 @@ static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; + ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL); if (!ec_rpmsg) return -ENOMEM; diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c index 8ca0f854e7ac..1b611ec5c9c1 100644 --- a/drivers/platform/chrome/cros_ec_spi.c +++ b/drivers/platform/chrome/cros_ec_spi.c @@ -10,6 +10,7 @@ #include <linux/platform_data/cros_ec_commands.h> #include <linux/platform_data/cros_ec_proto.h> #include <linux/platform_device.h> +#include <linux/revocable.h> #include <linux/slab.h> #include <linux/spi/spi.h> #include <uapi/linux/sched/types.h> @@ -752,6 +753,9 @@ static int cros_ec_spi_probe(struct spi_device *spi) ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; /* Check for any DT properties */ cros_ec_spi_dt_probe(ec_spi, dev); diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c index 19c179d49c90..b234f13a92a9 100644 --- a/drivers/platform/chrome/cros_ec_uart.c +++ b/drivers/platform/chrome/cros_ec_uart.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/of.h> #include <linux/platform_data/cros_ec_proto.h> +#include <linux/revocable.h> #include <linux/serdev.h> #include <linux/slab.h> #include <uapi/linux/sched/types.h> @@ -263,6 +264,10 @@ static int cros_ec_uart_probe(struct serdev_device *serdev) if (!ec_dev) return -ENOMEM; + ec_dev->revocable_provider = devm_revocable_provider_alloc(dev, ec_dev); + if (!ec_dev->revocable_provider) + return -ENOMEM; + serdev_device_set_drvdata(serdev, ec_dev); init_waitqueue_head(&ec_uart->response.wait_queue); diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h index 3ec24f445c29..0c3df0bb0aa4 100644 --- a/include/linux/platform_data/cros_ec_proto.h +++ b/include/linux/platform_data/cros_ec_proto.h @@ -12,6 +12,7 @@ #include <linux/lockdep_types.h> #include <linux/mutex.h> #include <linux/notifier.h> +#include <linux/revocable.h> #include <linux/platform_data/cros_ec_commands.h> @@ -158,6 +159,7 @@ struct cros_ec_command { * @pd: The platform_device used by the mfd driver to interface with the * PD behind an EC. * @panic_notifier: EC panic notifier. + * @revocable_provider: The revocable_provider to this device. */ struct cros_ec_device { /* These are used by other drivers that want to talk to the EC */ @@ -203,6 +205,8 @@ struct cros_ec_device { struct platform_device *pd; struct blocking_notifier_head panic_notifier; + + struct revocable_provider *revocable_provider; }; /** -- 2.51.0.rc1.167.g924127e9c0-goog
