5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> commit 9a71892cbcdb9d1459c84f5a4c722b14354158a5 upstream. This reverts commit 15fffc6a5624b13b428bb1c6e9088e32a55eb82c. This commit causes a regression, so revert it for now until it can come back in a way that works for everyone. Link: https://lore.kernel.org/all/172790598832.1168608.4519484276671503678.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx/ Fixes: 15fffc6a5624 ("driver core: Fix uevent_show() vs driver detach race") Cc: stable <stable@xxxxxxxxxx> Cc: Ashish Sangwan <a.sangwan@xxxxxxxxxxx> Cc: Namjae Jeon <namjae.jeon@xxxxxxxxxxx> Cc: Dirk Behme <dirk.behme@xxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/base/core.c | 13 +++++-------- drivers/base/module.c | 4 ---- 2 files changed, 5 insertions(+), 12 deletions(-) --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -25,7 +25,6 @@ #include <linux/mutex.h> #include <linux/pm_runtime.h> #include <linux/netdevice.h> -#include <linux/rcupdate.h> #include <linux/sched/signal.h> #include <linux/sysfs.h> @@ -1175,7 +1174,6 @@ static int dev_uevent(struct kset *kset, struct kobj_uevent_env *env) { struct device *dev = kobj_to_dev(kobj); - struct device_driver *driver; int retval = 0; /* add device node properties if present */ @@ -1204,12 +1202,8 @@ static int dev_uevent(struct kset *kset, if (dev->type && dev->type->name) add_uevent_var(env, "DEVTYPE=%s", dev->type->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(); + if (dev->driver) + add_uevent_var(env, "DRIVER=%s", dev->driver->name); /* Add common DT information about the device */ of_device_uevent(dev, env); @@ -1279,8 +1273,11 @@ static ssize_t uevent_show(struct device if (!env) return -ENOMEM; + /* Synchronize with really_probe() */ + device_lock(dev); /* let the kset specific function add its keys */ retval = kset->uevent_ops->uevent(kset, &dev->kobj, env); + device_unlock(dev); if (retval) goto out; --- a/drivers/base/module.c +++ b/drivers/base/module.c @@ -7,7 +7,6 @@ #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) @@ -78,9 +77,6 @@ void module_remove_driver(struct device_ if (!drv) return; - /* Synchronize with dev_uevent() */ - synchronize_rcu(); - sysfs_remove_link(&drv->p->kobj, "module"); if (drv->owner)
