Ingo,
I just found a __MAJOR__ bug in my code. Below is the patch that fixes
this bug, zaps the WARN_ON in check_pi_list_present, and changes
ALL_TASKS_PI to a booleon instead of just a define.
The major bug was in __down_trylock. See anything wrong with this
code :-) I'm surprised that this worked as well as it did!
if (likely(!old_owner) || __grab_lock(lock, task, old_owner->task)) {
/* granted */
TRACE_WARN_ON_LOCKED(!plist_empty(&lock->wait_list) &&
!old_owner);
if (old_owner) {
__raw_spin_lock(&old_owner->task->pi_lock);
set_new_owner(lock, old_owner, ti __EIP__);
__raw_spin_unlock(&old_owner->task->pi_lock);
} else
set_new_owner(lock, old_owner, ti __EIP__);
__raw_spin_unlock(&lock->wait_lock);
__raw_spin_unlock(&task->pi_lock);
ret = 1;
}
__raw_spin_unlock(&lock->wait_lock);
__raw_spin_unlock(&task->pi_lock);
Here's the patch:
-- Steve
Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]>
Index: linux_realtime_goliath/kernel/rt.c
===================================================================
--- linux_realtime_goliath/kernel/rt.c (revision 314)
+++ linux_realtime_goliath/kernel/rt.c (working copy)
@@ -104,7 +104,7 @@
* in the system fall under PI handling. Normally only SCHED_FIFO/RR
* tasks are PI-handled:
*/
-#define ALL_TASKS_PI
+#define ALL_TASKS_PI 1
#ifdef CONFIG_RT_DEADLOCK_DETECT
# define __EIP_DECL__ , unsigned long eip
@@ -663,7 +663,7 @@
#endif
-#if defined(ALL_TASKS_PI) && defined(CONFIG_RT_DEADLOCK_DETECT)
+#if ALL_TASKS_PI && defined(CONFIG_RT_DEADLOCK_DETECT)
static void
check_pi_list_present(struct rt_mutex *lock, struct rt_mutex_waiter *waiter,
@@ -674,7 +674,6 @@
__raw_spin_lock(&old_owner->task->pi_lock);
TRACE_WARN_ON_LOCKED(plist_empty(&waiter->pi_list));
- TRACE_WARN_ON_LOCKED(lock_owner(lock));
plist_for_each(curr1, &old_owner->task->pi_waiters) {
w = plist_entry(curr1, struct rt_mutex_waiter, pi_list);
@@ -851,7 +850,7 @@
__raw_spin_lock(&l->wait_lock);
TRACE_BUG_ON_LOCKED(!lock_owner(l));
- if (rt_task(p) && plist_empty(&w->pi_list)) {
+ if ((ALL_TASKS_PI || rt_task(p)) && plist_empty(&w->pi_list)) {
TRACE_BUG_ON_LOCKED(was_rt);
plist_init(&w->pi_list, prio);
plist_add(&w->pi_list,
&lock_owner(l)->task->pi_waiters);
@@ -868,7 +867,7 @@
* (TODO: this can be unfair to SCHED_NORMAL tasks if they
* get PI handled.)
*/
- if (!rt_task(p) && !plist_empty(&w->pi_list)) {
+ if (!ALL_TASKS_PI && !rt_task(p) && !plist_empty(&w->pi_list)) {
TRACE_BUG_ON_LOCKED(!was_rt);
plist_del(&w->pi_list,
&lock_owner(l)->task->pi_waiters);
plist_del(&w->list, &l->wait_list);
@@ -970,7 +969,7 @@
*/
TRACE_BUG_ON_LOCKED(!spin_is_locked(&task->pi_lock));
TRACE_BUG_ON_LOCKED(!spin_is_locked(&lock->wait_lock));
-#ifndef ALL_TASKS_PI
+#if !ALL_TASKS_PI
if (!rt_task(task)) {
plist_add(&waiter->list, &lock->wait_list);
set_lock_owner_pending(lock);
@@ -1071,6 +1070,7 @@
struct rt_mutex_waiter *waiter = NULL;
struct thread_info *new_owner;
+ TRACE_BUG_ON_LOCKED(!spin_is_locked(&lock->wait_lock));
/*
* Get the highest prio one:
*
@@ -1083,7 +1083,7 @@
#endif
trace_special_pid(waiter->ti->task->pid, waiter->ti->task->prio, 0);
-#ifdef ALL_TASKS_PI
+#if ALL_TASKS_PI
check_pi_list_present(lock, waiter, old_owner);
#endif
new_owner = waiter->ti;
@@ -1543,7 +1543,7 @@
list_del_init(&lock->held_list);
#endif
-#ifdef ALL_TASKS_PI
+#if ALL_TASKS_PI
if (plist_empty(&lock->wait_list))
check_pi_list_empty(lock, lock_owner(lock));
#endif
@@ -1906,8 +1906,6 @@
__raw_spin_unlock(&old_owner->task->pi_lock);
} else
set_new_owner(lock, old_owner, ti __EIP__);
- __raw_spin_unlock(&lock->wait_lock);
- __raw_spin_unlock(&task->pi_lock);
ret = 1;
}
__raw_spin_unlock(&lock->wait_lock);
-
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