4.19-stable review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman gregkh@linuxfoundation.org
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@d... Fixes: 15fffc6a5624 ("driver core: Fix uevent_show() vs driver detach race") Cc: stable stable@kernel.org Cc: Ashish Sangwan a.sangwan@samsung.com Cc: Namjae Jeon namjae.jeon@samsung.com Cc: Dirk Behme dirk.behme@de.bosch.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Rafael J. Wysocki rafael@kernel.org Cc: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -24,7 +24,6 @@ #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>
@@ -1138,7 +1137,6 @@ 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 */ @@ -1167,12 +1165,8 @@ 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); @@ -1242,8 +1236,11 @@ 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)