[PATCH 4/6] nptl: Revert TPP updates on pthread_mutex_*lock failure (bug 34546)

Also fix __pthread_tpp_change_priority to undo changes to the priomap
array if any of the scheduler system calls fail.
---
 nptl/pthread_mutex_lock.c      | 12 +++++-------
 nptl/pthread_mutex_timedlock.c | 21 +++++++--------------
 nptl/pthread_mutex_trylock.c   | 12 +++++-------
 nptl/tpp.c                     | 19 +++++++++++++++++++
 sysdeps/nptl/pthreadP.h        |  4 ++++
 5 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
index a697f2b6ca..82ffc4204f 100644
--- a/nptl/pthread_mutex_lock.c
+++ b/nptl/pthread_mutex_lock.c
@@ -534,15 +534,13 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
 			  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 
 	    if (__pthread_current_priority () > ceiling)
-	      {
-		if (oldprio != -1)
-		  __pthread_tpp_change_priority (oldprio, -1);
-		return EINVAL;
-	      }
+	      return __pthread_mutex_priority_error (EINVAL, oldprio);
 
 	    int retval = __pthread_tpp_change_priority (oldprio, ceiling);
-	    if (retval)
-	      return retval;
+	    if (retval != 0)
+	      /* Undo the adjustment from the previous loop iteration
+		 (if any, first iteration has -1 and skips adjustment).  */
+	      return __pthread_mutex_priority_error (retval, oldprio);
 
 	    ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 	    oldprio = ceiling;
diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index 3b8bb1ddfd..2a44108736 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -468,17 +468,13 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex,
 			  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 
 	    if (__pthread_current_priority () > ceiling)
-	      {
-		result = EINVAL;
-	      failpp:
-		if (oldprio != -1)
-		  __pthread_tpp_change_priority (oldprio, -1);
-		return result;
-	      }
+	      return __pthread_mutex_priority_error (EINVAL, oldprio);
 
 	    result = __pthread_tpp_change_priority (oldprio, ceiling);
-	    if (result)
-	      return result;
+	    if (result != 0)
+	      /* Undo the adjustment from the previous loop iteration
+		 (if any, first iteration has -1 and skips adjustment).  */
+	      return __pthread_mutex_priority_error (result, oldprio);
 
 	    ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 	    oldprio = ceiling;
@@ -504,16 +500,13 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex,
 		  {
 		    /* Reject invalid timeouts.  */
 		    if (! valid_nanoseconds (abstime->tv_nsec))
-		      {
-			result = EINVAL;
-			goto failpp;
-		      }
+		      return __pthread_mutex_priority_error (EINVAL, oldprio);
 
 		    int e = __futex_abstimed_wait64 (
 		      (unsigned int *) &mutex->__data.__lock, ceilval | 2,
 		      clockid, abstime, PTHREAD_MUTEX_PSHARED (mutex));
 		    if (e == ETIMEDOUT || e == EOVERFLOW)
-		      return e;
+		      return __pthread_mutex_priority_error (e, oldprio);
 		  }
 	      }
 	    while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c
index 236b3228dd..15786fda09 100644
--- a/nptl/pthread_mutex_trylock.c
+++ b/nptl/pthread_mutex_trylock.c
@@ -396,15 +396,13 @@ ___pthread_mutex_trylock (pthread_mutex_t *mutex)
 			  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 
 	    if (__pthread_current_priority () > ceiling)
-	      {
-		if (oldprio != -1)
-		  __pthread_tpp_change_priority (oldprio, -1);
-		return EINVAL;
-	      }
+	      return __pthread_mutex_priority_error (EINVAL, oldprio);
 
 	    int retval = __pthread_tpp_change_priority (oldprio, ceiling);
-	    if (retval)
-	      return retval;
+	    if (retval != 0)
+	      /* Undo the adjustment from the previous loop iteration
+		 (if any, first iteration has -1 and skips adjustment).  */
+	      return __pthread_mutex_priority_error (retval, oldprio);
 
 	    ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
 	    oldprio = ceiling;
diff --git a/nptl/tpp.c b/nptl/tpp.c
index 2674f36564..627ef1dc6d 100644
--- a/nptl/tpp.c
+++ b/nptl/tpp.c
@@ -152,6 +152,17 @@ __pthread_tpp_change_priority (int previous_prio, int new_prio)
 	}
     }
 
+  /* Roll back the TPP bookkeeping information if the scheduler
+     reconfiguration failed.  */
+  if (result != 0)
+    {
+      tpp->priomax = priomax;
+      if (new_prio != -1)
+	--tpp->priomap[new_prio - fifo_min_prio];
+      if (previous_prio != -1)
+	++tpp->priomap[previous_prio - fifo_min_prio];
+    }
+
   lll_unlock (self->lock, LLL_PRIVATE);
 
   return result;
@@ -196,3 +207,11 @@ __pthread_current_priority (void)
   return result;
 }
 libc_hidden_def (__pthread_current_priority)
+
+int
+__pthread_mutex_priority_error (int err, int oldprio)
+{
+  if (oldprio != -1)
+    __pthread_tpp_change_priority (oldprio, -1);
+  return err;
+}
diff --git a/sysdeps/nptl/pthreadP.h b/sysdeps/nptl/pthreadP.h
index de432d4032..982705aee5 100644
--- a/sysdeps/nptl/pthreadP.h
+++ b/sysdeps/nptl/pthreadP.h
@@ -211,6 +211,10 @@ libc_hidden_proto (__pthread_tpp_change_priority)
 extern int __pthread_current_priority (void);
 libc_hidden_proto (__pthread_current_priority)
 
+/* If OLDPRIO is not -1, undo its TPP priority change.  Return ERR.  */
+int __pthread_mutex_priority_error (int err, int oldprio) attribute_hidden;
+
+
 /* This will not catch all invalid descriptors but is better than
    nothing.  And if the test triggers the thread descriptor is
    guaranteed to be invalid.  */
-- 
2.55.0