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locking/rtmutex: Remove output from deadlock detector

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The rtmutex specific deadlock detector predates lockdep coverage of rtmutex
and since commit f5694788ad ("rt_mutex: Add lockdep annotations") it
contains a lot of redundant functionality:

 - lockdep will detect an potential deadlock before rtmutex-debug
   has a chance to do so

 - the deadlock debugging is restricted to rtmutexes which are not
   associated to futexes and have an active waiter, which is covered by
   lockdep already

Remove the redundant functionality and move actual deadlock WARN() into the
deadlock code path. The latter needs a seperate cleanup.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210326153943.320398604@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior
2021-03-26 16:29:32 +01:00
committed by Ingo Molnar
parent 2d445c3e4a
commit 6d41c675a5
6 changed files with 1 additions and 130 deletions
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7
kernel/locking/rtmutex.c
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@@ -579,7 +579,6 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
* walk, we detected a deadlock.
*/
if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
debug_rt_mutex_deadlock(chwalk, orig_waiter, lock);
raw_spin_unlock(&lock->wait_lock);
ret = -EDEADLK;
goto out_unlock_pi;
@@ -1171,8 +1170,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
raw_spin_unlock_irq(&lock->wait_lock);
debug_rt_mutex_print_deadlock(waiter);
schedule();
raw_spin_lock_irq(&lock->wait_lock);
@@ -1196,7 +1193,7 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
/*
* Yell loudly and stop the task right here.
*/
rt_mutex_print_deadlock(w);
WARN(1, "rtmutex deadlock detected\n");
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
@@ -1704,8 +1701,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
ret = 0;
}
debug_rt_mutex_print_deadlock(waiter);
return ret;
}