Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "The main change in this cycle are initial preparatory bits of dynamic
  lockdep keys support from Bart Van Assche.

  There are also misc changes, a comment cleanup and a data structure
  cleanup"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Clean up comment in nohz_idle_balance()
  locking/lockdep: Stop using RCU primitives to access 'all_lock_classes'
  locking/lockdep: Make concurrent lockdep_reset_lock() calls safe
  locking/lockdep: Remove a superfluous INIT_LIST_HEAD() statement
  locking/lockdep: Introduce lock_class_cache_is_registered()
  locking/lockdep: Inline __lockdep_init_map()
  locking/lockdep: Declare local symbols static
  tools/lib/lockdep/tests: Test the lockdep_reset_lock() implementation
  tools/lib/lockdep: Add dummy print_irqtrace_events() implementation
  tools/lib/lockdep: Rename "trywlock" into "trywrlock"
  tools/lib/lockdep/tests: Run lockdep tests a second time under Valgrind
  tools/lib/lockdep/tests: Improve testing accuracy
  tools/lib/lockdep/tests: Fix shellcheck warnings
  tools/lib/lockdep/tests: Display compiler warning and error messages
  locking/lockdep: Remove ::version from lock_class structure

26 files changed, 131 insertions, 53 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 1fd82ff99c65..c5335df2372f 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -97,8 +97,6 @@ struct lock_class {
          * Generation counter, when doing certain classes of graph walking,
          * to ensure that we check one node only once:
          */
-        unsigned int                    version;
-
         int                             name_version;
         const char                      *name;
 
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ef27f98714c0..95932333a48b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -138,6 +138,9 @@ static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
  * get freed - this significantly simplifies the debugging code.
  */
 unsigned long nr_lock_classes;
+#ifndef CONFIG_DEBUG_LOCKDEP
+static
+#endif
 struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
 
 static inline struct lock_class *hlock_class(struct held_lock *hlock)
@@ -626,7 +629,8 @@ static int static_obj(void *obj)
 
 /*
  * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
+ * class->name_version generation counter. The caller must hold the graph
+ * lock.
  */
 static int count_matching_names(struct lock_class *new_class)
 {
@@ -636,7 +640,7 @@ static int count_matching_names(struct lock_class *new_class)
         if (!new_class->name)
                 return 0;
 
-        list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
+        list_for_each_entry(class, &all_lock_classes, lock_entry) {
                 if (new_class->key - new_class->subclass == class->key)
                         return class->name_version;
                 if (class->name && !strcmp(class->name, new_class->name))
@@ -789,7 +793,6 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
         class->key = key;
         class->name = lock->name;
         class->subclass = subclass;
-        INIT_LIST_HEAD(&class->lock_entry);
         INIT_LIST_HEAD(&class->locks_before);
         INIT_LIST_HEAD(&class->locks_after);
         class->name_version = count_matching_names(class);
@@ -801,7 +804,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
         /*
          * Add it to the global list of classes:
          */
-        list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
+        list_add_tail(&class->lock_entry, &all_lock_classes);
 
         if (verbose(class)) {
                 graph_unlock();
@@ -3088,7 +3091,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 /*
  * Initialize a lock instance's lock-class mapping info:
  */
-static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
                       struct lock_class_key *key, int subclass)
 {
         int i;
@@ -3144,12 +3147,6 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
                 raw_local_irq_restore(flags);
         }
 }
-
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
-                      struct lock_class_key *key, int subclass)
-{
-        __lockdep_init_map(lock, name, key, subclass);
-}
 EXPORT_SYMBOL_GPL(lockdep_init_map);
 
 struct lock_class_key __lockdep_no_validate__;
@@ -4126,6 +4123,9 @@ void lockdep_reset(void)
         raw_local_irq_restore(flags);
 }
 
+/*
+ * Remove all references to a lock class. The caller must hold the graph lock.
+ */
 static void zap_class(struct lock_class *class)
 {
         int i;
@@ -4142,7 +4142,7 @@ static void zap_class(struct lock_class *class)
          * Unhash the class and remove it from the all_lock_classes list:
          */
         hlist_del_rcu(&class->hash_entry);
-        list_del_rcu(&class->lock_entry);
+        list_del(&class->lock_entry);
 
         RCU_INIT_POINTER(class->key, NULL);
         RCU_INIT_POINTER(class->name, NULL);
@@ -4204,15 +4204,36 @@ void lockdep_free_key_range(void *start, unsigned long size)
          */
 }
 
-void lockdep_reset_lock(struct lockdep_map *lock)
+/*
+ * Check whether any element of the @lock->class_cache[] array refers to a
+ * registered lock class. The caller must hold either the graph lock or the
+ * RCU read lock.
+ */
+static bool lock_class_cache_is_registered(struct lockdep_map *lock)
 {
         struct lock_class *class;
         struct hlist_head *head;
-        unsigned long flags;
         int i, j;
-        int locked;
+
+        for (i = 0; i < CLASSHASH_SIZE; i++) {
+                head = classhash_table + i;
+                hlist_for_each_entry_rcu(class, head, hash_entry) {
+                        for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
+                                if (lock->class_cache[j] == class)
+                                        return true;
+                }
+        }
+        return false;
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+        struct lock_class *class;
+        unsigned long flags;
+        int j, locked;
 
         raw_local_irq_save(flags);
+        locked = graph_lock();
 
         /*
          * Remove all classes this lock might have:
@@ -4229,25 +4250,14 @@ void lockdep_reset_lock(struct lockdep_map *lock)
          * Debug check: in the end all mapped classes should
          * be gone.
          */
-        locked = graph_lock();
-        for (i = 0; i < CLASSHASH_SIZE; i++) {
-                head = classhash_table + i;
-                hlist_for_each_entry_rcu(class, head, hash_entry) {
-                        int match = 0;
-
-                        for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
-                                match |= class == lock->class_cache[j];
-
-                        if (unlikely(match)) {
-                                if (debug_locks_off_graph_unlock()) {
-                                        /*
-                                         * We all just reset everything, how did it match?
-                                         */
-                                        WARN_ON(1);
-                                }
-                                goto out_restore;
-                        }
+        if (unlikely(lock_class_cache_is_registered(lock))) {
+                if (debug_locks_off_graph_unlock()) {
+                        /*
+                         * We all just reset everything, how did it match?
+                         */
+                        WARN_ON(1);
                 }
+                goto out_restore;
         }
         if (locked)
                 graph_unlock();
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ac855b2f4774..db514993565b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9533,9 +9533,7 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
                 return false;
         }
 
-        /*
-         * barrier, pairs with nohz_balance_enter_idle(), ensures ...
-         */
+        /* could be _relaxed() */
         flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(this_cpu));
         if (!(flags & NOHZ_KICK_MASK))
                 return false;
diff --git a/tools/lib/lockdep/include/liblockdep/common.h b/tools/lib/lockdep/include/liblockdep/common.h
index 8862da80995a..d640a9761f09 100644
--- a/tools/lib/lockdep/include/liblockdep/common.h
+++ b/tools/lib/lockdep/include/liblockdep/common.h
@@ -44,6 +44,7 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                         struct lockdep_map *nest_lock, unsigned long ip);
 void lock_release(struct lockdep_map *lock, int nested,
                         unsigned long ip);
+void lockdep_reset_lock(struct lockdep_map *lock);
 extern void debug_check_no_locks_freed(const void *from, unsigned long len);
 
 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
diff --git a/tools/lib/lockdep/include/liblockdep/mutex.h b/tools/lib/lockdep/include/liblockdep/mutex.h
index a80ac39f966e..2073d4e1f2f0 100644
--- a/tools/lib/lockdep/include/liblockdep/mutex.h
+++ b/tools/lib/lockdep/include/liblockdep/mutex.h
@@ -54,6 +54,7 @@ static inline int liblockdep_pthread_mutex_trylock(liblockdep_pthread_mutex_t *l
 
 static inline int liblockdep_pthread_mutex_destroy(liblockdep_pthread_mutex_t *lock)
 {
+        lockdep_reset_lock(&lock->dep_map);
         return pthread_mutex_destroy(&lock->mutex);
 }
 
diff --git a/tools/lib/lockdep/include/liblockdep/rwlock.h b/tools/lib/lockdep/include/liblockdep/rwlock.h
index a96c3bf0fef1..365762e3a1ea 100644
--- a/tools/lib/lockdep/include/liblockdep/rwlock.h
+++ b/tools/lib/lockdep/include/liblockdep/rwlock.h
@@ -60,10 +60,10 @@ static inline int liblockdep_pthread_rwlock_tryrdlock(liblockdep_pthread_rwlock_
         return pthread_rwlock_tryrdlock(&lock->rwlock) == 0 ? 1 : 0;
 }
 
-static inline int liblockdep_pthread_rwlock_trywlock(liblockdep_pthread_rwlock_t *lock)
+static inline int liblockdep_pthread_rwlock_trywrlock(liblockdep_pthread_rwlock_t *lock)
 {
         lock_acquire(&lock->dep_map, 0, 1, 0, 1, NULL, (unsigned long)_RET_IP_);
-        return pthread_rwlock_trywlock(&lock->rwlock) == 0 ? 1 : 0;
+        return pthread_rwlock_trywrlock(&lock->rwlock) == 0 ? 1 : 0;
 }
 
 static inline int liblockdep_rwlock_destroy(liblockdep_pthread_rwlock_t *lock)
@@ -79,7 +79,7 @@ static inline int liblockdep_rwlock_destroy(liblockdep_pthread_rwlock_t *lock)
 #define pthread_rwlock_unlock           liblockdep_pthread_rwlock_unlock
 #define pthread_rwlock_wrlock           liblockdep_pthread_rwlock_wrlock
 #define pthread_rwlock_tryrdlock        liblockdep_pthread_rwlock_tryrdlock
-#define pthread_rwlock_trywlock         liblockdep_pthread_rwlock_trywlock
+#define pthread_rwlock_trywrlock        liblockdep_pthread_rwlock_trywrlock
 #define pthread_rwlock_destroy          liblockdep_rwlock_destroy
 
 #endif
diff --git a/tools/lib/lockdep/lockdep.c b/tools/lib/lockdep/lockdep.c
index 6002fcf2f9bc..348a9d0fb766 100644
--- a/tools/lib/lockdep/lockdep.c
+++ b/tools/lib/lockdep/lockdep.c
@@ -15,6 +15,11 @@ u32 prandom_u32(void)
         abort();
 }
 
+void print_irqtrace_events(struct task_struct *curr)
+{
+        abort();
+}
+
 static struct new_utsname *init_utsname(void)
 {
         static struct new_utsname n = (struct new_utsname) {
diff --git a/tools/lib/lockdep/run_tests.sh b/tools/lib/lockdep/run_tests.sh
index 2e570a188f16..c8fbd0306960 100755
--- a/tools/lib/lockdep/run_tests.sh
+++ b/tools/lib/lockdep/run_tests.sh
@@ -1,32 +1,47 @@
 #! /bin/bash
 # SPDX-License-Identifier: GPL-2.0
 
-make &> /dev/null
+if ! make >/dev/null; then
+    echo "Building liblockdep failed."
+    echo "FAILED!"
+    exit 1
+fi
 
-for i in `ls tests/*.c`; do
+find tests -name '*.c' | sort | while read -r i; do
         testname=$(basename "$i" .c)
-        gcc -o tests/$testname -pthread $i liblockdep.a -Iinclude -D__USE_LIBLOCKDEP &> /dev/null
         echo -ne "$testname... "
-        if [ $(timeout 1 ./tests/$testname 2>&1 | wc -l) -gt 0 ]; then
+        if gcc -o "tests/$testname" -pthread "$i" liblockdep.a -Iinclude -D__USE_LIBLOCKDEP &&
+                timeout 1 "tests/$testname" 2>&1 | "tests/${testname}.sh"; then
                 echo "PASSED!"
         else
                 echo "FAILED!"
         fi
-        if [ -f "tests/$testname" ]; then
-                rm tests/$testname
-        fi
+        rm -f "tests/$testname"
 done
 
-for i in `ls tests/*.c`; do
+find tests -name '*.c' | sort | while read -r i; do
         testname=$(basename "$i" .c)
-        gcc -o tests/$testname -pthread -Iinclude $i &> /dev/null
         echo -ne "(PRELOAD) $testname... "
-        if [ $(timeout 1 ./lockdep ./tests/$testname 2>&1 | wc -l) -gt 0 ]; then
+        if gcc -o "tests/$testname" -pthread -Iinclude "$i" &&
+                timeout 1 ./lockdep "tests/$testname" 2>&1 |
+                "tests/${testname}.sh"; then
                 echo "PASSED!"
         else
                 echo "FAILED!"
         fi
-        if [ -f "tests/$testname" ]; then
-                rm tests/$testname
+        rm -f "tests/$testname"
+done
+
+find tests -name '*.c' | sort | while read -r i; do
+        testname=$(basename "$i" .c)
+        echo -ne "(PRELOAD + Valgrind) $testname... "
+        if gcc -o "tests/$testname" -pthread -Iinclude "$i" &&
+                { timeout 10 valgrind --read-var-info=yes ./lockdep "./tests/$testname" >& "tests/${testname}.vg.out"; true; } &&
+                "tests/${testname}.sh" < "tests/${testname}.vg.out" &&
+                ! grep -Eq '(^==[0-9]*== (Invalid |Uninitialised ))|Mismatched free|Source and destination overlap| UME ' "tests/${testname}.vg.out"; then
+                echo "PASSED!"
+        else
+                echo "FAILED!"
         fi
+        rm -f "tests/$testname"
 done
diff --git a/tools/lib/lockdep/tests/AA.sh b/tools/lib/lockdep/tests/AA.sh
new file mode 100644
index 000000000000..f39b32865074
--- /dev/null
+++ b/tools/lib/lockdep/tests/AA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible recursive locking detected'
diff --git a/tools/lib/lockdep/tests/ABA.sh b/tools/lib/lockdep/tests/ABA.sh
new file mode 100644
index 000000000000..f39b32865074
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible recursive locking detected'
diff --git a/tools/lib/lockdep/tests/ABBA.c b/tools/lib/lockdep/tests/ABBA.c
index 1460afd33d71..623313f54720 100644
--- a/tools/lib/lockdep/tests/ABBA.c
+++ b/tools/lib/lockdep/tests/ABBA.c
@@ -11,4 +11,7 @@ void main(void)
 
         LOCK_UNLOCK_2(a, b);
         LOCK_UNLOCK_2(b, a);
+
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABBA.sh b/tools/lib/lockdep/tests/ABBA.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABBA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABBA_2threads.sh b/tools/lib/lockdep/tests/ABBA_2threads.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABBA_2threads.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABBCCA.c b/tools/lib/lockdep/tests/ABBCCA.c
index a54c1b2af118..48446129d496 100644
--- a/tools/lib/lockdep/tests/ABBCCA.c
+++ b/tools/lib/lockdep/tests/ABBCCA.c
@@ -13,4 +13,8 @@ void main(void)
         LOCK_UNLOCK_2(a, b);
         LOCK_UNLOCK_2(b, c);
         LOCK_UNLOCK_2(c, a);
+
+        pthread_mutex_destroy(&c);
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABBCCA.sh b/tools/lib/lockdep/tests/ABBCCA.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABBCCA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABBCCDDA.c b/tools/lib/lockdep/tests/ABBCCDDA.c
index aa5d194e8869..3570bf7b3804 100644
--- a/tools/lib/lockdep/tests/ABBCCDDA.c
+++ b/tools/lib/lockdep/tests/ABBCCDDA.c
@@ -15,4 +15,9 @@ void main(void)
         LOCK_UNLOCK_2(b, c);
         LOCK_UNLOCK_2(c, d);
         LOCK_UNLOCK_2(d, a);
+
+        pthread_mutex_destroy(&d);
+        pthread_mutex_destroy(&c);
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABBCCDDA.sh b/tools/lib/lockdep/tests/ABBCCDDA.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABBCCDDA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABCABC.c b/tools/lib/lockdep/tests/ABCABC.c
index b54a08e60416..a1c4659894cd 100644
--- a/tools/lib/lockdep/tests/ABCABC.c
+++ b/tools/lib/lockdep/tests/ABCABC.c
@@ -13,4 +13,8 @@ void main(void)
         LOCK_UNLOCK_2(a, b);
         LOCK_UNLOCK_2(c, a);
         LOCK_UNLOCK_2(b, c);
+
+        pthread_mutex_destroy(&c);
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABCABC.sh b/tools/lib/lockdep/tests/ABCABC.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABCABC.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABCDBCDA.c b/tools/lib/lockdep/tests/ABCDBCDA.c
index a56742250d86..335af1c90ab5 100644
--- a/tools/lib/lockdep/tests/ABCDBCDA.c
+++ b/tools/lib/lockdep/tests/ABCDBCDA.c
@@ -15,4 +15,9 @@ void main(void)
         LOCK_UNLOCK_2(c, d);
         LOCK_UNLOCK_2(b, c);
         LOCK_UNLOCK_2(d, a);
+
+        pthread_mutex_destroy(&d);
+        pthread_mutex_destroy(&c);
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABCDBCDA.sh b/tools/lib/lockdep/tests/ABCDBCDA.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABCDBCDA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/ABCDBDDA.c b/tools/lib/lockdep/tests/ABCDBDDA.c
index 238a3353f3c3..3c5972863049 100644
--- a/tools/lib/lockdep/tests/ABCDBDDA.c
+++ b/tools/lib/lockdep/tests/ABCDBDDA.c
@@ -15,4 +15,9 @@ void main(void)
         LOCK_UNLOCK_2(c, d);
         LOCK_UNLOCK_2(b, d);
         LOCK_UNLOCK_2(d, a);
+
+        pthread_mutex_destroy(&d);
+        pthread_mutex_destroy(&c);
+        pthread_mutex_destroy(&b);
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/ABCDBDDA.sh b/tools/lib/lockdep/tests/ABCDBDDA.sh
new file mode 100644
index 000000000000..fc31c607a5a8
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABCDBDDA.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible circular locking dependency detected'
diff --git a/tools/lib/lockdep/tests/WW.sh b/tools/lib/lockdep/tests/WW.sh
new file mode 100644
index 000000000000..f39b32865074
--- /dev/null
+++ b/tools/lib/lockdep/tests/WW.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: possible recursive locking detected'
diff --git a/tools/lib/lockdep/tests/unlock_balance.c b/tools/lib/lockdep/tests/unlock_balance.c
index 34cf32f689de..dba25064b50a 100644
--- a/tools/lib/lockdep/tests/unlock_balance.c
+++ b/tools/lib/lockdep/tests/unlock_balance.c
@@ -10,4 +10,6 @@ void main(void)
         pthread_mutex_lock(&a);
         pthread_mutex_unlock(&a);
         pthread_mutex_unlock(&a);
+
+        pthread_mutex_destroy(&a);
 }
diff --git a/tools/lib/lockdep/tests/unlock_balance.sh b/tools/lib/lockdep/tests/unlock_balance.sh
new file mode 100644
index 000000000000..c6e3952303fe
--- /dev/null
+++ b/tools/lib/lockdep/tests/unlock_balance.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+grep -q 'WARNING: bad unlock balance detected'