5.4-stable review patch. If anyone has any objections, please let me know.
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From: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org
commit bb17d110cbf270d5247a6e261c5ad50e362d1675 upstream.
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@linar... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Lee Jones lee@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/rpmsg/rpmsg_core.c | 33 ++++++++++++++++++++++++++++++--- drivers/rpmsg/rpmsg_internal.h | 14 +------------- include/linux/rpmsg.h | 8 ++++++++ 3 files changed, 39 insertions(+), 16 deletions(-)
--- a/drivers/rpmsg/rpmsg_core.c +++ b/drivers/rpmsg/rpmsg_core.c @@ -526,24 +526,51 @@ 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);
/* --- a/drivers/rpmsg/rpmsg_internal.h +++ b/drivers/rpmsg/rpmsg_internal.h @@ -84,19 +84,7 @@ struct device *rpmsg_find_device(struct */ static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev) { - int ret; - - strcpy(rpdev->id.name, "rpmsg_chrdev"); - 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 --- a/include/linux/rpmsg.h +++ b/include/linux/rpmsg.h @@ -115,6 +115,8 @@ struct rpmsg_driver {
#if IS_ENABLED(CONFIG_RPMSG)
+int rpmsg_register_device_override(struct rpmsg_device *rpdev, + const char *driver_override); int register_rpmsg_device(struct rpmsg_device *dev); void unregister_rpmsg_device(struct rpmsg_device *dev); int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner); @@ -139,6 +141,12 @@ __poll_t rpmsg_poll(struct rpmsg_endpoin
#else
+static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev, + const char *driver_override) +{ + return -ENXIO; +} + static inline int register_rpmsg_device(struct rpmsg_device *dev) { return -ENXIO;