Merge tag 'locking-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Core locking primitives updates:
    - Remove mutex_trylock_recursive() from the API - no users left
    - Simplify + constify the futex code a bit

  Lockdep updates:
    - Teach lockdep about local_lock_t
    - Add CONFIG_DEBUG_IRQFLAGS=y debug config option to check for
      potentially unsafe IRQ mask restoration patterns. (I.e.
      calling raw_local_irq_restore() with IRQs enabled.)
    - Add wait context self-tests
    - Fix graph lock corner case corrupting internal data structures
    - Fix noinstr annotations

  LKMM updates:
    - Simplify the litmus tests
    - Documentation fixes

  KCSAN updates:
    - Re-enable KCSAN instrumentation in lib/random32.c

  Misc fixes:
    - Don't branch-trace static label APIs
    - DocBook fix
    - Remove stale leftover empty file"

* tag 'locking-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  checkpatch: Don't check for mutex_trylock_recursive()
  locking/mutex: Kill mutex_trylock_recursive()
  s390: Use arch_local_irq_{save,restore}() in early boot code
  lockdep: Noinstr annotate warn_bogus_irq_restore()
  locking/lockdep: Avoid unmatched unlock
  locking/rwsem: Remove empty rwsem.h
  locking/rtmutex: Add missing kernel-doc markup
  futex: Remove unneeded gotos
  futex: Change utime parameter to be 'const ... *'
  lockdep: report broken irq restoration
  jump_label: Do not profile branch annotations
  locking: Add Reviewers
  locking/selftests: Add local_lock inversion tests
  locking/lockdep: Exclude local_lock_t from IRQ inversions
  locking/lockdep: Clean up check_redundant() a bit
  locking/lockdep: Add a skip() function to __bfs()
  locking/lockdep: Mark local_lock_t
  locking/selftests: More granular debug_locks_verbose
  lockdep/selftest: Add wait context selftests
  tools/memory-model: Fix typo in klitmus7 compatibility table
  ...

3 files changed, 340 insertions, 5 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7937265ef879..5ea0c1773b0a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1335,6 +1335,7 @@ config LOCKDEP_SMALL
 config DEBUG_LOCKDEP
 	bool "Lock dependency engine debugging"
 	depends on DEBUG_KERNEL && LOCKDEP
+	select DEBUG_IRQFLAGS
 	help
 	  If you say Y here, the lock dependency engine will do
 	  additional runtime checks to debug itself, at the price
@@ -1423,6 +1424,13 @@ config TRACE_IRQFLAGS_NMI
 	depends on TRACE_IRQFLAGS
 	depends on TRACE_IRQFLAGS_NMI_SUPPORT
 
+config DEBUG_IRQFLAGS
+	bool "Debug IRQ flag manipulation"
+	help
+	  Enables checks for potentially unsafe enabling or disabling of
+	  interrupts, such as calling raw_local_irq_restore() when interrupts
+	  are enabled.
+
 config STACKTRACE
 	bool "Stack backtrace support"
 	depends on STACKTRACE_SUPPORT
diff --git a/lib/Makefile b/lib/Makefile
index a6b160c3a4fa..fb7d946bb8c3 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -27,9 +27,6 @@ KASAN_SANITIZE_string.o := n
 CFLAGS_string.o += -fno-stack-protector
 endif
 
-# Used by KCSAN while enabled, avoid recursion.
-KCSAN_SANITIZE_random32.o := n
-
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o timerqueue.o xarray.o \
 	 idr.o extable.o sha1.o irq_regs.o argv_split.o \
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 9959ea23529e..2d85abac1744 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -24,6 +24,7 @@
 #include <linux/debug_locks.h>
 #include <linux/irqflags.h>
 #include <linux/rtmutex.h>
+#include <linux/local_lock.h>
 
 /*
  * Change this to 1 if you want to see the failure printouts:
@@ -51,6 +52,7 @@ __setup("debug_locks_verbose=", setup_debug_locks_verbose);
 #define LOCKTYPE_RWSEM	0x8
 #define LOCKTYPE_WW	0x10
 #define LOCKTYPE_RTMUTEX 0x20
+#define LOCKTYPE_LL	0x40
 
 static struct ww_acquire_ctx t, t2;
 static struct ww_mutex o, o2, o3;
@@ -64,6 +66,9 @@ static DEFINE_SPINLOCK(lock_B);
 static DEFINE_SPINLOCK(lock_C);
 static DEFINE_SPINLOCK(lock_D);
 
+static DEFINE_RAW_SPINLOCK(raw_lock_A);
+static DEFINE_RAW_SPINLOCK(raw_lock_B);
+
 static DEFINE_RWLOCK(rwlock_A);
 static DEFINE_RWLOCK(rwlock_B);
 static DEFINE_RWLOCK(rwlock_C);
@@ -133,6 +138,8 @@ static DEFINE_RT_MUTEX(rtmutex_Z2);
 
 #endif
 
+static local_lock_t local_A = INIT_LOCAL_LOCK(local_A);
+
 /*
  * non-inlined runtime initializers, to let separate locks share
  * the same lock-class:
@@ -1306,19 +1313,23 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define I_SPINLOCK(x)	lockdep_reset_lock(&lock_##x.dep_map)
+# define I_RAW_SPINLOCK(x)	lockdep_reset_lock(&raw_lock_##x.dep_map)
 # define I_RWLOCK(x)	lockdep_reset_lock(&rwlock_##x.dep_map)
 # define I_MUTEX(x)	lockdep_reset_lock(&mutex_##x.dep_map)
 # define I_RWSEM(x)	lockdep_reset_lock(&rwsem_##x.dep_map)
 # define I_WW(x)	lockdep_reset_lock(&x.dep_map)
+# define I_LOCAL_LOCK(x) lockdep_reset_lock(&local_##x.dep_map)
 #ifdef CONFIG_RT_MUTEXES
 # define I_RTMUTEX(x)	lockdep_reset_lock(&rtmutex_##x.dep_map)
 #endif
 #else
 # define I_SPINLOCK(x)
+# define I_RAW_SPINLOCK(x)
 # define I_RWLOCK(x)
 # define I_MUTEX(x)
 # define I_RWSEM(x)
 # define I_WW(x)
+# define I_LOCAL_LOCK(x)
 #endif
 
 #ifndef I_RTMUTEX
@@ -1358,9 +1369,16 @@ static void reset_locks(void)
 	I1(A); I1(B); I1(C); I1(D);
 	I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
 	I_WW(t); I_WW(t2); I_WW(o.base); I_WW(o2.base); I_WW(o3.base);
+	I_RAW_SPINLOCK(A); I_RAW_SPINLOCK(B);
+	I_LOCAL_LOCK(A);
+
 	lockdep_reset();
+
 	I2(A); I2(B); I2(C); I2(D);
 	init_shared_classes();
+	raw_spin_lock_init(&raw_lock_A);
+	raw_spin_lock_init(&raw_lock_B);
+	local_lock_init(&local_A);
 
 	ww_mutex_init(&o, &ww_lockdep); ww_mutex_init(&o2, &ww_lockdep); ww_mutex_init(&o3, &ww_lockdep);
 	memset(&t, 0, sizeof(t)); memset(&t2, 0, sizeof(t2));
@@ -1382,6 +1400,8 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
 
 	WARN_ON(irqs_disabled());
 
+	debug_locks_silent = !(debug_locks_verbose & lockclass_mask);
+
 	testcase_fn();
 	/*
 	 * Filter out expected failures:
@@ -1402,7 +1422,7 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
 	}
 	testcase_total++;
 
-	if (debug_locks_verbose)
+	if (debug_locks_verbose & lockclass_mask)
 		pr_cont(" lockclass mask: %x, debug_locks: %d, expected: %d\n",
 			lockclass_mask, debug_locks, expected);
 	/*
@@ -2419,6 +2439,311 @@ static void fs_reclaim_tests(void)
 	pr_cont("\n");
 }
 
+#define __guard(cleanup) __maybe_unused __attribute__((__cleanup__(cleanup)))
+
+static void hardirq_exit(int *_)
+{
+	HARDIRQ_EXIT();
+}
+
+#define HARDIRQ_CONTEXT(name, ...)					\
+	int hardirq_guard_##name __guard(hardirq_exit);			\
+	HARDIRQ_ENTER();
+
+#define NOTTHREADED_HARDIRQ_CONTEXT(name, ...)				\
+	int notthreaded_hardirq_guard_##name __guard(hardirq_exit);	\
+	local_irq_disable();						\
+	__irq_enter();							\
+	WARN_ON(!in_irq());
+
+static void softirq_exit(int *_)
+{
+	SOFTIRQ_EXIT();
+}
+
+#define SOFTIRQ_CONTEXT(name, ...)				\
+	int softirq_guard_##name __guard(softirq_exit);		\
+	SOFTIRQ_ENTER();
+
+static void rcu_exit(int *_)
+{
+	rcu_read_unlock();
+}
+
+#define RCU_CONTEXT(name, ...)					\
+	int rcu_guard_##name __guard(rcu_exit);			\
+	rcu_read_lock();
+
+static void rcu_bh_exit(int *_)
+{
+	rcu_read_unlock_bh();
+}
+
+#define RCU_BH_CONTEXT(name, ...)				\
+	int rcu_bh_guard_##name __guard(rcu_bh_exit);		\
+	rcu_read_lock_bh();
+
+static void rcu_sched_exit(int *_)
+{
+	rcu_read_unlock_sched();
+}
+
+#define RCU_SCHED_CONTEXT(name, ...)				\
+	int rcu_sched_guard_##name __guard(rcu_sched_exit);	\
+	rcu_read_lock_sched();
+
+static void rcu_callback_exit(int *_)
+{
+	rcu_lock_release(&rcu_callback_map);
+}
+
+#define RCU_CALLBACK_CONTEXT(name, ...)					\
+	int rcu_callback_guard_##name __guard(rcu_callback_exit);	\
+	rcu_lock_acquire(&rcu_callback_map);
+
+
+static void raw_spinlock_exit(raw_spinlock_t **lock)
+{
+	raw_spin_unlock(*lock);
+}
+
+#define RAW_SPINLOCK_CONTEXT(name, lock)						\
+	raw_spinlock_t *raw_spinlock_guard_##name __guard(raw_spinlock_exit) = &(lock);	\
+	raw_spin_lock(&(lock));
+
+static void spinlock_exit(spinlock_t **lock)
+{
+	spin_unlock(*lock);
+}
+
+#define SPINLOCK_CONTEXT(name, lock)						\
+	spinlock_t *spinlock_guard_##name __guard(spinlock_exit) = &(lock);	\
+	spin_lock(&(lock));
+
+static void mutex_exit(struct mutex **lock)
+{
+	mutex_unlock(*lock);
+}
+
+#define MUTEX_CONTEXT(name, lock)					\
+	struct mutex *mutex_guard_##name __guard(mutex_exit) = &(lock);	\
+	mutex_lock(&(lock));
+
+#define GENERATE_2_CONTEXT_TESTCASE(outer, outer_lock, inner, inner_lock)	\
+										\
+static void __maybe_unused inner##_in_##outer(void)				\
+{										\
+	outer##_CONTEXT(_, outer_lock);						\
+	{									\
+		inner##_CONTEXT(_, inner_lock);					\
+	}									\
+}
+
+/*
+ * wait contexts (considering PREEMPT_RT)
+ *
+ * o: inner is allowed in outer
+ * x: inner is disallowed in outer
+ *
+ *       \  inner |  RCU  | RAW_SPIN | SPIN | MUTEX
+ * outer  \       |       |          |      |
+ * ---------------+-------+----------+------+-------
+ * HARDIRQ        |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * NOTTHREADED_IRQ|   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * SOFTIRQ        |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU            |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_BH         |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_CALLBACK   |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_SCHED      |   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * RAW_SPIN       |   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * SPIN           |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * MUTEX          |   o   |    o     |  o   |  o
+ * ---------------+-------+----------+------+-------
+ */
+
+#define GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(HARDIRQ, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(NOTTHREADED_HARDIRQ, , inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(SOFTIRQ, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU, , inner, inner_lock)				\
+GENERATE_2_CONTEXT_TESTCASE(RCU_BH, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU_CALLBACK, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU_SCHED, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RAW_SPINLOCK, raw_lock_A, inner, inner_lock)	\
+GENERATE_2_CONTEXT_TESTCASE(SPINLOCK, lock_A, inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(MUTEX, mutex_A, inner, inner_lock)
+
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RCU, )
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RAW_SPINLOCK, raw_lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(SPINLOCK, lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(MUTEX, mutex_B)
+
+/* the outer context allows all kinds of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(outer)			\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, SUCCESS, LOCKTYPE_MUTEX);		\
+
+/*
+ * the outer context only allows the preemption introduced by spinlock_t (which
+ * is a sleepable lock for PREEMPT_RT)
+ */
+#define DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(outer)		\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX);		\
+
+/* the outer doesn't allows any kind of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(outer)			\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, FAILURE, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX);		\
+
+static void wait_context_tests(void)
+{
+	printk("  --------------------------------------------------------------------------\n");
+	printk("  | wait context tests |\n");
+	printk("  --------------------------------------------------------------------------\n");
+	printk("                                 | rcu  | raw  | spin |mutex |\n");
+	printk("  --------------------------------------------------------------------------\n");
+	print_testname("in hardirq context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(HARDIRQ);
+	pr_cont("\n");
+
+	print_testname("in hardirq context (not threaded)");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(NOTTHREADED_HARDIRQ);
+	pr_cont("\n");
+
+	print_testname("in softirq context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SOFTIRQ);
+	pr_cont("\n");
+
+	print_testname("in RCU context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU);
+	pr_cont("\n");
+
+	print_testname("in RCU-bh context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_BH);
+	pr_cont("\n");
+
+	print_testname("in RCU callback context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_CALLBACK);
+	pr_cont("\n");
+
+	print_testname("in RCU-sched context");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RCU_SCHED);
+	pr_cont("\n");
+
+	print_testname("in RAW_SPINLOCK context");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RAW_SPINLOCK);
+	pr_cont("\n");
+
+	print_testname("in SPINLOCK context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SPINLOCK);
+	pr_cont("\n");
+
+	print_testname("in MUTEX context");
+	DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(MUTEX);
+	pr_cont("\n");
+}
+
+static void local_lock_2(void)
+{
+	local_lock_acquire(&local_A);	/* IRQ-ON */
+	local_lock_release(&local_A);
+
+	HARDIRQ_ENTER();
+	spin_lock(&lock_A);		/* IN-IRQ */
+	spin_unlock(&lock_A);
+	HARDIRQ_EXIT()
+
+	HARDIRQ_DISABLE();
+	spin_lock(&lock_A);
+	local_lock_acquire(&local_A);	/* IN-IRQ <-> IRQ-ON cycle, false */
+	local_lock_release(&local_A);
+	spin_unlock(&lock_A);
+	HARDIRQ_ENABLE();
+}
+
+static void local_lock_3A(void)
+{
+	local_lock_acquire(&local_A);	/* IRQ-ON */
+	spin_lock(&lock_B);		/* IRQ-ON */
+	spin_unlock(&lock_B);
+	local_lock_release(&local_A);
+
+	HARDIRQ_ENTER();
+	spin_lock(&lock_A);		/* IN-IRQ */
+	spin_unlock(&lock_A);
+	HARDIRQ_EXIT()
+
+	HARDIRQ_DISABLE();
+	spin_lock(&lock_A);
+	local_lock_acquire(&local_A);	/* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */
+	local_lock_release(&local_A);
+	spin_unlock(&lock_A);
+	HARDIRQ_ENABLE();
+}
+
+static void local_lock_3B(void)
+{
+	local_lock_acquire(&local_A);	/* IRQ-ON */
+	spin_lock(&lock_B);		/* IRQ-ON */
+	spin_unlock(&lock_B);
+	local_lock_release(&local_A);
+
+	HARDIRQ_ENTER();
+	spin_lock(&lock_A);		/* IN-IRQ */
+	spin_unlock(&lock_A);
+	HARDIRQ_EXIT()
+
+	HARDIRQ_DISABLE();
+	spin_lock(&lock_A);
+	local_lock_acquire(&local_A);	/* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */
+	local_lock_release(&local_A);
+	spin_unlock(&lock_A);
+	HARDIRQ_ENABLE();
+
+	HARDIRQ_DISABLE();
+	spin_lock(&lock_A);
+	spin_lock(&lock_B);		/* IN-IRQ <-> IRQ-ON cycle, true */
+	spin_unlock(&lock_B);
+	spin_unlock(&lock_A);
+	HARDIRQ_DISABLE();
+
+}
+
+static void local_lock_tests(void)
+{
+	printk("  --------------------------------------------------------------------------\n");
+	printk("  | local_lock tests |\n");
+	printk("  ---------------------\n");
+
+	print_testname("local_lock inversion  2");
+	dotest(local_lock_2, SUCCESS, LOCKTYPE_LL);
+	pr_cont("\n");
+
+	print_testname("local_lock inversion 3A");
+	dotest(local_lock_3A, SUCCESS, LOCKTYPE_LL);
+	pr_cont("\n");
+
+	print_testname("local_lock inversion 3B");
+	dotest(local_lock_3B, FAILURE, LOCKTYPE_LL);
+	pr_cont("\n");
+}
+
 void locking_selftest(void)
 {
 	/*
@@ -2446,7 +2771,6 @@ void locking_selftest(void)
 	printk("  --------------------------------------------------------------------------\n");
 
 	init_shared_classes();
-	debug_locks_silent = !debug_locks_verbose;
 	lockdep_set_selftest_task(current);
 
 	DO_TESTCASE_6R("A-A deadlock", AA);
@@ -2542,6 +2866,12 @@ void locking_selftest(void)
 
 	fs_reclaim_tests();
 
+	/* Wait context test cases that are specific for RAW_LOCK_NESTING */
+	if (IS_ENABLED(CONFIG_PROVE_RAW_LOCK_NESTING))
+		wait_context_tests();
+
+	local_lock_tests();
+
 	if (unexpected_testcase_failures) {
 		printk("-----------------------------------------------------------------\n");
 		debug_locks = 0;