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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-03 11:37:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-03 11:37:15 -0700
commit542a086ac72fb193cbc1b996963a572269e57743 (patch)
treeb137c08037cca4ffc8a156a891a01113b3b8edce /lib
parent1d1fdd95df681f0c065d90ffaafa215a0e8825e2 (diff)
parent1eeeef153c02f5856ec109fa532eb5f31c39f85c (diff)
downloadop-kernel-dev-542a086ac72fb193cbc1b996963a572269e57743.zip
op-kernel-dev-542a086ac72fb193cbc1b996963a572269e57743.tar.gz
Merge tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg KH: "Here's the big driver core pull request for 3.12-rc1. Lots of tiny changes here fixing up the way sysfs attributes are created, to try to make drivers simpler, and fix a whole class race conditions with creations of device attributes after the device was announced to userspace. All the various pieces are acked by the different subsystem maintainers" * tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (119 commits) firmware loader: fix pending_fw_head list corruption drivers/base/memory.c: introduce help macro to_memory_block dynamic debug: line queries failing due to uninitialized local variable sysfs: sysfs_create_groups returns a value. debugfs: provide debugfs_create_x64() when disabled rbd: convert bus code to use bus_groups firmware: dcdbas: use binary attribute groups sysfs: add sysfs_create/remove_groups for when SYSFS is not enabled driver core: add #include <linux/sysfs.h> to core files. HID: convert bus code to use dev_groups Input: serio: convert bus code to use drv_groups Input: gameport: convert bus code to use drv_groups driver core: firmware: use __ATTR_RW() driver core: core: use DEVICE_ATTR_RO driver core: bus: use DRIVER_ATTR_WO() driver core: create write-only attribute macros for devices and drivers sysfs: create __ATTR_WO() driver-core: platform: convert bus code to use dev_groups workqueue: convert bus code to use dev_groups MEI: convert bus code to use dev_groups ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug19
-rw-r--r--lib/dynamic_debug.c2
-rw-r--r--lib/kobject.c22
3 files changed, 39 insertions, 4 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1501aa5..444e1c1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -981,6 +981,25 @@ config DEBUG_KOBJECT
If you say Y here, some extra kobject debugging messages will be sent
to the syslog.
+config DEBUG_KOBJECT_RELEASE
+ bool "kobject release debugging"
+ depends on DEBUG_KERNEL
+ help
+ kobjects are reference counted objects. This means that their
+ last reference count put is not predictable, and the kobject can
+ live on past the point at which a driver decides to drop it's
+ initial reference to the kobject gained on allocation. An
+ example of this would be a struct device which has just been
+ unregistered.
+
+ However, some buggy drivers assume that after such an operation,
+ the memory backing the kobject can be immediately freed. This
+ goes completely against the principles of a refcounted object.
+
+ If you say Y here, the kernel will delay the release of kobjects
+ on the last reference count to improve the visibility of this
+ kind of kobject release bug.
+
config HAVE_DEBUG_BUGVERBOSE
bool
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 99fec3a..c37aeac 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -309,7 +309,7 @@ static int ddebug_parse_query(char *words[], int nwords,
struct ddebug_query *query, const char *modname)
{
unsigned int i;
- int rc;
+ int rc = 0;
/* check we have an even number of words */
if (nwords % 2 != 0) {
diff --git a/lib/kobject.c b/lib/kobject.c
index 4a1f33d..1d46c15 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -545,8 +545,8 @@ static void kobject_cleanup(struct kobject *kobj)
struct kobj_type *t = get_ktype(kobj);
const char *name = kobj->name;
- pr_debug("kobject: '%s' (%p): %s\n",
- kobject_name(kobj), kobj, __func__);
+ pr_debug("kobject: '%s' (%p): %s, parent %p\n",
+ kobject_name(kobj), kobj, __func__, kobj->parent);
if (t && !t->release)
pr_debug("kobject: '%s' (%p): does not have a release() "
@@ -580,9 +580,25 @@ static void kobject_cleanup(struct kobject *kobj)
}
}
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+static void kobject_delayed_cleanup(struct work_struct *work)
+{
+ kobject_cleanup(container_of(to_delayed_work(work),
+ struct kobject, release));
+}
+#endif
+
static void kobject_release(struct kref *kref)
{
- kobject_cleanup(container_of(kref, struct kobject, kref));
+ struct kobject *kobj = container_of(kref, struct kobject, kref);
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+ pr_debug("kobject: '%s' (%p): %s, parent %p (delayed)\n",
+ kobject_name(kobj), kobj, __func__, kobj->parent);
+ INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
+ schedule_delayed_work(&kobj->release, HZ);
+#else
+ kobject_cleanup(kobj);
+#endif
}
/**
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