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authorDu, Changbin <changbin.du@intel.com>2016-05-19 17:09:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-19 19:12:14 -0700
commitb9fdac7f660609abb157500e468d2165b3c9cf08 (patch)
tree37d3b704f52b46dfb6d9ebb24611870dbb2b93be /kernel
parent8bad1cd0e1edd124c0f05f925762ef84e6047586 (diff)
downloadlinux-sh-b9fdac7f660609abb157500e468d2165b3c9cf08.tar.gz
debugobjects: insulate non-fixup logic related to static obj from fixup callbacks
When activating a static object we need make sure that the object is tracked in the object tracker. If it is a non-static object then the activation is illegal. In previous implementation, each subsystem need take care of this in their fixup callbacks. Actually we can put it into debugobjects core. Thus we can save duplicated code, and have *pure* fixup callbacks. To achieve this, a new callback "is_static_object" is introduced to let the type specific code decide whether a object is static or not. If yes, we take it into object tracker, otherwise give warning and invoke fixup callback. This change has paassed debugobjects selftest, and I also do some test with all debugobjects supports enabled. At last, I have a concern about the fixups that can it change the object which is in incorrect state on fixup? Because the 'addr' may not point to any valid object if a non-static object is not tracked. Then Change such object can overwrite someone's memory and cause unexpected behaviour. For example, the timer_fixup_activate bind timer to function stub_timer. Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com [changbin.du@intel.com: improve code comments where invoke the new is_static_object callback] Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcu/update.c26
-rw-r--r--kernel/time/hrtimer.c7
-rw-r--r--kernel/time/timer.c43
-rw-r--r--kernel/workqueue.c42
4 files changed, 26 insertions, 92 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index a9df198eb22d..3e888cd5a594 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -380,29 +380,9 @@ void destroy_rcu_head(struct rcu_head *head)
debug_object_free(head, &rcuhead_debug_descr);
}
-/*
- * fixup_activate is called when:
- * - an active object is activated
- * - an unknown object is activated (might be a statically initialized object)
- * Activation is performed internally by call_rcu().
- */
-static bool rcuhead_fixup_activate(void *addr, enum debug_obj_state state)
+static bool rcuhead_is_static_object(void *addr)
{
- struct rcu_head *head = addr;
-
- switch (state) {
-
- case ODEBUG_STATE_NOTAVAILABLE:
- /*
- * This is not really a fixup. We just make sure that it is
- * tracked in the object tracker.
- */
- debug_object_init(head, &rcuhead_debug_descr);
- debug_object_activate(head, &rcuhead_debug_descr);
- return false;
- default:
- return true;
- }
+ return true;
}
/**
@@ -440,7 +420,7 @@ EXPORT_SYMBOL_GPL(destroy_rcu_head_on_stack);
struct debug_obj_descr rcuhead_debug_descr = {
.name = "rcu_head",
- .fixup_activate = rcuhead_fixup_activate,
+ .is_static_object = rcuhead_is_static_object,
};
EXPORT_SYMBOL_GPL(rcuhead_debug_descr);
#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index f962a58c0957..8c7392c4fdbd 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -351,16 +351,11 @@ static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
/*
* fixup_activate is called when:
* - an active object is activated
- * - an unknown object is activated (might be a statically initialized object)
+ * - an unknown non-static object is activated
*/
static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
{
switch (state) {
-
- case ODEBUG_STATE_NOTAVAILABLE:
- WARN_ON_ONCE(1);
- return false;
-
case ODEBUG_STATE_ACTIVE:
WARN_ON(1);
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index be33481a4da1..3a95f9728778 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -489,6 +489,14 @@ static void *timer_debug_hint(void *addr)
return ((struct timer_list *) addr)->function;
}
+static bool timer_is_static_object(void *addr)
+{
+ struct timer_list *timer = addr;
+
+ return (timer->entry.pprev == NULL &&
+ timer->entry.next == TIMER_ENTRY_STATIC);
+}
+
/*
* fixup_init is called when:
* - an active object is initialized
@@ -516,30 +524,16 @@ static void stub_timer(unsigned long data)
/*
* fixup_activate is called when:
* - an active object is activated
- * - an unknown object is activated (might be a statically initialized object)
+ * - an unknown non-static object is activated
*/
static bool timer_fixup_activate(void *addr, enum debug_obj_state state)
{
struct timer_list *timer = addr;
switch (state) {
-
case ODEBUG_STATE_NOTAVAILABLE:
- /*
- * This is not really a fixup. The timer was
- * statically initialized. We just make sure that it
- * is tracked in the object tracker.
- */
- if (timer->entry.pprev == NULL &&
- timer->entry.next == TIMER_ENTRY_STATIC) {
- debug_object_init(timer, &timer_debug_descr);
- debug_object_activate(timer, &timer_debug_descr);
- return false;
- } else {
- setup_timer(timer, stub_timer, 0);
- return true;
- }
- return false;
+ setup_timer(timer, stub_timer, 0);
+ return true;
case ODEBUG_STATE_ACTIVE:
WARN_ON(1);
@@ -577,18 +571,8 @@ static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state)
switch (state) {
case ODEBUG_STATE_NOTAVAILABLE:
- if (timer->entry.next == TIMER_ENTRY_STATIC) {
- /*
- * This is not really a fixup. The timer was
- * statically initialized. We just make sure that it
- * is tracked in the object tracker.
- */
- debug_object_init(timer, &timer_debug_descr);
- return false;
- } else {
- setup_timer(timer, stub_timer, 0);
- return true;
- }
+ setup_timer(timer, stub_timer, 0);
+ return true;
default:
return false;
}
@@ -597,6 +581,7 @@ static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state)
static struct debug_obj_descr timer_debug_descr = {
.name = "timer_list",
.debug_hint = timer_debug_hint,
+ .is_static_object = timer_is_static_object,
.fixup_init = timer_fixup_init,
.fixup_activate = timer_fixup_activate,
.fixup_free = timer_fixup_free,
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6751b18fd9ac..e1c0e996b5ae 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -433,6 +433,13 @@ static void *work_debug_hint(void *addr)
return ((struct work_struct *) addr)->func;
}
+static bool work_is_static_object(void *addr)
+{
+ struct work_struct *work = addr;
+
+ return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work));
+}
+
/*
* fixup_init is called when:
* - an active object is initialized
@@ -452,39 +459,6 @@ static bool work_fixup_init(void *addr, enum debug_obj_state state)
}
/*
- * fixup_activate is called when:
- * - an active object is activated
- * - an unknown object is activated (might be a statically initialized object)
- */
-static bool work_fixup_activate(void *addr, enum debug_obj_state state)
-{
- struct work_struct *work = addr;
-
- switch (state) {
-
- case ODEBUG_STATE_NOTAVAILABLE:
- /*
- * This is not really a fixup. The work struct was
- * statically initialized. We just make sure that it
- * is tracked in the object tracker.
- */
- if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) {
- debug_object_init(work, &work_debug_descr);
- debug_object_activate(work, &work_debug_descr);
- return false;
- }
- WARN_ON_ONCE(1);
- return false;
-
- case ODEBUG_STATE_ACTIVE:
- WARN_ON(1);
-
- default:
- return false;
- }
-}
-
-/*
* fixup_free is called when:
* - an active object is freed
*/
@@ -505,8 +479,8 @@ static bool work_fixup_free(void *addr, enum debug_obj_state state)
static struct debug_obj_descr work_debug_descr = {
.name = "work_struct",
.debug_hint = work_debug_hint,
+ .is_static_object = work_is_static_object,
.fixup_init = work_fixup_init,
- .fixup_activate = work_fixup_activate,
.fixup_free = work_fixup_free,
};