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-rw-r--r--include/linux/lockdep.h23
-rw-r--r--kernel/locking/lockdep.c14
-rw-r--r--lib/locking-selftest.c11
3 files changed, 47 insertions, 1 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 6a584b3e5c74..7cae5ea00d59 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -469,6 +469,20 @@ static inline void print_irqtrace_events(struct task_struct *curr)
}
#endif
+/* Variable used to make lockdep treat read_lock() as recursive in selftests */
+#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
+extern unsigned int force_read_lock_recursive;
+#else /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
+#define force_read_lock_recursive 0
+#endif /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
+
+#ifdef CONFIG_LOCKDEP
+extern bool read_lock_is_recursive(void);
+#else /* CONFIG_LOCKDEP */
+/* If !LOCKDEP, the value is meaningless */
+#define read_lock_is_recursive() 0
+#endif
+
/*
* For trivial one-depth nesting of a lock-class, the following
* global define can be used. (Subsystems with multiple levels
@@ -490,7 +504,14 @@ static inline void print_irqtrace_events(struct task_struct *curr)
#define spin_release(l, i) lock_release(l, i)
#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
-#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
+#define rwlock_acquire_read(l, s, t, i) \
+do { \
+ if (read_lock_is_recursive()) \
+ lock_acquire_shared_recursive(l, s, t, NULL, i); \
+ else \
+ lock_acquire_shared(l, s, t, NULL, i); \
+} while (0)
+
#define rwlock_release(l, i) lock_release(l, i)
#define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 54b74fabf40c..77cd9e6520c4 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4968,6 +4968,20 @@ static bool lockdep_nmi(void)
}
/*
+ * read_lock() is recursive if:
+ * 1. We force lockdep think this way in selftests or
+ * 2. The implementation is not queued read/write lock or
+ * 3. The locker is at an in_interrupt() context.
+ */
+bool read_lock_is_recursive(void)
+{
+ return force_read_lock_recursive ||
+ !IS_ENABLED(CONFIG_QUEUED_RWLOCKS) ||
+ in_interrupt();
+}
+EXPORT_SYMBOL_GPL(read_lock_is_recursive);
+
+/*
* We are not always called with irqs disabled - do that here,
* and also avoid lockdep recursion:
*/
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 14f44f59e733..caadc4dd3368 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -28,6 +28,7 @@
* Change this to 1 if you want to see the failure printouts:
*/
static unsigned int debug_locks_verbose;
+unsigned int force_read_lock_recursive;
static DEFINE_WD_CLASS(ww_lockdep);
@@ -1979,6 +1980,11 @@ void locking_selftest(void)
}
/*
+ * treats read_lock() as recursive read locks for testing purpose
+ */
+ force_read_lock_recursive = 1;
+
+ /*
* Run the testsuite:
*/
printk("------------------------\n");
@@ -2073,6 +2079,11 @@ void locking_selftest(void)
ww_tests();
+ force_read_lock_recursive = 0;
+ /*
+ * queued_read_lock() specific test cases can be put here
+ */
+
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
debug_locks = 0;