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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-09-04 13:07:52 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-09-04 13:07:52 -0700 |
| commit | bbcc0c699929d3b01ecf3066a35799defe733dd2 (patch) | |
| tree | 5fd368175f54e652b663ebd33dc78e174a288445 /kobject-delayed-kobject-release-help-find-buggy-drivers.patch | |
| parent | cba9545b635d1566060d5a8f1a9dc78680f4e839 (diff) | |
| download | patches-bbcc0c699929d3b01ecf3066a35799defe733dd2.tar.gz | |
remove a bunch of patches now in Linus's tree
Diffstat (limited to 'kobject-delayed-kobject-release-help-find-buggy-drivers.patch')
| -rw-r--r-- | kobject-delayed-kobject-release-help-find-buggy-drivers.patch | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/kobject-delayed-kobject-release-help-find-buggy-drivers.patch b/kobject-delayed-kobject-release-help-find-buggy-drivers.patch deleted file mode 100644 index cdae1a841c82e6..00000000000000 --- a/kobject-delayed-kobject-release-help-find-buggy-drivers.patch +++ /dev/null @@ -1,125 +0,0 @@ -From rmk+greg=kroah.com@arm.linux.org.uk Thu Jun 27 07:06:26 2013 -From: Russell King <rmk@arm.linux.org.uk> -Date: Thu, 27 Jun 2013 15:06:14 +0100 -Subject: kobject: delayed kobject release: help find buggy drivers -To: Greg KH <greg@kroah.com> -Cc: Linux Kernel List <linux-kernel@vger.kernel.org>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org> -Message-ID: <20130627140613.GB12530@flint.arm.linux.org.uk> - - -From: Russell King <rmk+kernel@arm.linux.org.uk> - -Implement debugging for kobject release functions. kobjects are -reference counted, so the drop of the last reference to them is not -predictable. However, the common case is for the last reference to be -the kobject's removal from a subsystem, which results in the release -function being immediately called. - -This can hide subtle bugs, which can occur when another thread holds a -reference to the kobject at the same time that a kobject is removed. -This results in the release method being delayed. - -In order to make these kinds of problems more visible, the following -patch implements a delayed release; this has the effect that the -release function will be out of order with respect to the removal of -the kobject in the same manner that it would be if a reference was -being held. - -This provides us with an easy way to allow driver writers to debug -their drivers and fix otherwise hidden problems. - -Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> ---- - include/linux/kobject.h | 4 ++++ - lib/Kconfig.debug | 19 +++++++++++++++++++ - lib/kobject.c | 22 +++++++++++++++++++--- - 3 files changed, 42 insertions(+), 3 deletions(-) - ---- a/include/linux/kobject.h -+++ b/include/linux/kobject.h -@@ -26,6 +26,7 @@ - #include <linux/kernel.h> - #include <linux/wait.h> - #include <linux/atomic.h> -+#include <linux/workqueue.h> - - #define UEVENT_HELPER_PATH_LEN 256 - #define UEVENT_NUM_ENVP 32 /* number of env pointers */ -@@ -65,6 +66,9 @@ struct kobject { - struct kobj_type *ktype; - struct sysfs_dirent *sd; - struct kref kref; -+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE -+ struct delayed_work release; -+#endif - unsigned int state_initialized:1; - unsigned int state_in_sysfs:1; - unsigned int state_add_uevent_sent:1; ---- 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 - ---- a/lib/kobject.c -+++ b/lib/kobject.c -@@ -545,8 +545,8 @@ static void kobject_cleanup(struct kobje - 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 kobje - } - } - -+#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 - } - - /** |