hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IBH7EF -------------------------------------- This reverts commit 5e125aaa84dc006a227fb39f838b3a2e0a27c72f. This patch will reintroduce device_lock in uevent_show(), which has already cause deadlock in practice. Fixes: 5e125aaa84dc ("Revert "driver core: Fix uevent_show() vs driver detach race"") Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com> --- drivers/base/core.c | 13 ++++++++----- drivers/base/module.c | 4 ++++ 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 560a124eeb8d..0b2cf93d8e01 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -25,6 +25,7 @@ #include <linux/mutex.h> #include <linux/pm_runtime.h> #include <linux/netdevice.h> +#include <linux/rcupdate.h> #include <linux/sched/signal.h> #include <linux/sched/mm.h> #include <linux/string_helpers.h> @@ -2566,6 +2567,7 @@ static const char *dev_uevent_name(const struct kobject *kobj) static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env) { const struct device *dev = kobj_to_dev(kobj); + struct device_driver *driver; int retval = 0; /* add device node properties if present */ @@ -2594,8 +2596,12 @@ static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env) if (dev->type && dev->type->name) add_uevent_var(env, "DEVTYPE=%s", dev->type->name); - if (dev->driver) - add_uevent_var(env, "DRIVER=%s", dev->driver->name); + /* Synchronize with module_remove_driver() */ + rcu_read_lock(); + driver = READ_ONCE(dev->driver); + if (driver) + add_uevent_var(env, "DRIVER=%s", driver->name); + rcu_read_unlock(); /* Add common DT information about the device */ of_device_uevent(dev, env); @@ -2665,11 +2671,8 @@ static ssize_t uevent_show(struct device *dev, struct device_attribute *attr, if (!env) return -ENOMEM; - /* Synchronize with really_probe() */ - device_lock(dev); /* let the kset specific function add its keys */ retval = kset->uevent_ops->uevent(&dev->kobj, env); - device_unlock(dev); if (retval) goto out; diff --git a/drivers/base/module.c b/drivers/base/module.c index a33663d92256..0d5c5da367f7 100644 --- a/drivers/base/module.c +++ b/drivers/base/module.c @@ -7,6 +7,7 @@ #include <linux/errno.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/rcupdate.h> #include "base.h" static char *make_driver_name(struct device_driver *drv) @@ -101,6 +102,9 @@ void module_remove_driver(struct device_driver *drv) if (!drv) return; + /* Synchronize with dev_uevent() */ + synchronize_rcu(); + sysfs_remove_link(&drv->p->kobj, "module"); if (drv->owner) -- 2.22.0