diff options
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/core.c | 53 | ||||
| -rw-r--r-- | drivers/base/platform.c | 9 | ||||
| -rw-r--r-- | drivers/base/regmap/Kconfig | 2 |
3 files changed, 60 insertions, 4 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index eede79630ceb..f0dd8e38fee3 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1835,12 +1835,63 @@ static inline struct kobject *get_glue_dir(struct device *dev) */ static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) { + unsigned int ref; + /* see if we live in a "glue" directory */ if (!live_in_glue_dir(glue_dir, dev)) return; mutex_lock(&gdp_mutex); - if (!kobject_has_children(glue_dir)) + /** + * There is a race condition between removing glue directory + * and adding a new device under the glue directory. + * + * CPU1: CPU2: + * + * device_add() + * get_device_parent() + * class_dir_create_and_add() + * kobject_add_internal() + * create_dir() // create glue_dir + * + * device_add() + * get_device_parent() + * kobject_get() // get glue_dir + * + * device_del() + * cleanup_glue_dir() + * kobject_del(glue_dir) + * + * kobject_add() + * kobject_add_internal() + * create_dir() // in glue_dir + * sysfs_create_dir_ns() + * kernfs_create_dir_ns(sd) + * + * sysfs_remove_dir() // glue_dir->sd=NULL + * sysfs_put() // free glue_dir->sd + * + * // sd is freed + * kernfs_new_node(sd) + * kernfs_get(glue_dir) + * kernfs_add_one() + * kernfs_put() + * + * Before CPU1 remove last child device under glue dir, if CPU2 add + * a new device under glue dir, the glue_dir kobject reference count + * will be increase to 2 in kobject_get(k). And CPU2 has been called + * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir() + * and sysfs_put(). This result in glue_dir->sd is freed. + * + * Then the CPU2 will see a stale "empty" but still potentially used + * glue dir around in kernfs_new_node(). + * + * In order to avoid this happening, we also should make sure that + * kernfs_node for glue_dir is released in CPU1 only when refcount + * for glue_dir kobj is 1. + */ + ref = kref_read(&glue_dir->kref); + if (!kobject_has_children(glue_dir) && !--ref) kobject_del(glue_dir); kobject_put(glue_dir); mutex_unlock(&gdp_mutex); diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 506a0175a5a7..ec974ba9c0c4 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -157,8 +157,13 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) * the device will only expose one IRQ, and this fallback * allows a common code path across either kind of resource. */ - if (num == 0 && has_acpi_companion(&dev->dev)) - return acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); + if (num == 0 && has_acpi_companion(&dev->dev)) { + int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); + + /* Our callers expect -ENXIO for missing IRQs. */ + if (ret >= 0 || ret == -EPROBE_DEFER) + return ret; + } return -ENXIO; #endif diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig index a4984136c19d..0fd6f97ee523 100644 --- a/drivers/base/regmap/Kconfig +++ b/drivers/base/regmap/Kconfig @@ -44,7 +44,7 @@ config REGMAP_IRQ config REGMAP_SOUNDWIRE tristate - depends on SOUNDWIRE_BUS + depends on SOUNDWIRE config REGMAP_SCCB tristate |