1 files changed, 302 insertions, 0 deletions

diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
new file mode 100644
index 000000000000..0374a596cffa
--- /dev/null
+++ b/kernel/locking/spinlock_debug.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright 2005, Red Hat, Inc., Ingo Molnar
+ * Released under the General Public License (GPL).
+ *
+ * This file contains the spinlock/rwlock implementations for
+ * DEBUG_SPINLOCK.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/nmi.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+
+void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+                          struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+        /*
+         * Make sure we are not reinitializing a held lock:
+         */
+        debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+        lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+        lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+        lock->magic = SPINLOCK_MAGIC;
+        lock->owner = SPINLOCK_OWNER_INIT;
+        lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__raw_spin_lock_init);
+
+void __rwlock_init(rwlock_t *lock, const char *name,
+                   struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+        /*
+         * Make sure we are not reinitializing a held lock:
+         */
+        debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+        lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+        lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
+        lock->magic = RWLOCK_MAGIC;
+        lock->owner = SPINLOCK_OWNER_INIT;
+        lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__rwlock_init);
+
+static void spin_dump(raw_spinlock_t *lock, const char *msg)
+{
+        struct task_struct *owner = NULL;
+
+        if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
+                owner = lock->owner;
+        printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
+                msg, raw_smp_processor_id(),
+                current->comm, task_pid_nr(current));
+        printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
+                        ".owner_cpu: %d\n",
+                lock, lock->magic,
+                owner ? owner->comm : "<none>",
+                owner ? task_pid_nr(owner) : -1,
+                lock->owner_cpu);
+        dump_stack();
+}
+
+static void spin_bug(raw_spinlock_t *lock, const char *msg)
+{
+        if (!debug_locks_off())
+                return;
+
+        spin_dump(lock, msg);
+}
+
+#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
+
+static inline void
+debug_spin_lock_before(raw_spinlock_t *lock)
+{
+        SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
+        SPIN_BUG_ON(lock->owner == current, lock, "recursion");
+        SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+                                                        lock, "cpu recursion");
+}
+
+static inline void debug_spin_lock_after(raw_spinlock_t *lock)
+{
+        lock->owner_cpu = raw_smp_processor_id();
+        lock->owner = current;
+}
+
+static inline void debug_spin_unlock(raw_spinlock_t *lock)
+{
+        SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
+        SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
+        SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
+        SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+                                                        lock, "wrong CPU");
+        lock->owner = SPINLOCK_OWNER_INIT;
+        lock->owner_cpu = -1;
+}
+
+static void __spin_lock_debug(raw_spinlock_t *lock)
+{
+        u64 i;
+        u64 loops = loops_per_jiffy * HZ;
+
+        for (i = 0; i < loops; i++) {
+                if (arch_spin_trylock(&lock->raw_lock))
+                        return;
+                __delay(1);
+        }
+        /* lockup suspected: */
+        spin_dump(lock, "lockup suspected");
+#ifdef CONFIG_SMP
+        trigger_all_cpu_backtrace();
+#endif
+
+        /*
+         * The trylock above was causing a livelock.  Give the lower level arch
+         * specific lock code a chance to acquire the lock. We have already
+         * printed a warning/backtrace at this point. The non-debug arch
+         * specific code might actually succeed in acquiring the lock.  If it is
+         * not successful, the end-result is the same - there is no forward
+         * progress.
+         */
+        arch_spin_lock(&lock->raw_lock);
+}
+
+void do_raw_spin_lock(raw_spinlock_t *lock)
+{
+        debug_spin_lock_before(lock);
+        if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
+                __spin_lock_debug(lock);
+        debug_spin_lock_after(lock);
+}
+
+int do_raw_spin_trylock(raw_spinlock_t *lock)
+{
+        int ret = arch_spin_trylock(&lock->raw_lock);
+
+        if (ret)
+                debug_spin_lock_after(lock);
+#ifndef CONFIG_SMP
+        /*
+         * Must not happen on UP:
+         */
+        SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+        return ret;
+}
+
+void do_raw_spin_unlock(raw_spinlock_t *lock)
+{
+        debug_spin_unlock(lock);
+        arch_spin_unlock(&lock->raw_lock);
+}
+
+static void rwlock_bug(rwlock_t *lock, const char *msg)
+{
+        if (!debug_locks_off())
+                return;
+
+        printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
+                msg, raw_smp_processor_id(), current->comm,
+                task_pid_nr(current), lock);
+        dump_stack();
+}
+
+#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
+
+#if 0           /* __write_lock_debug() can lock up - maybe this can too? */
+static void __read_lock_debug(rwlock_t *lock)
+{
+        u64 i;
+        u64 loops = loops_per_jiffy * HZ;
+        int print_once = 1;
+
+        for (;;) {
+                for (i = 0; i < loops; i++) {
+                        if (arch_read_trylock(&lock->raw_lock))
+                                return;
+                        __delay(1);
+                }
+                /* lockup suspected: */
+                if (print_once) {
+                        print_once = 0;
+                        printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
+                                        "%s/%d, %p\n",
+                                raw_smp_processor_id(), current->comm,
+                                current->pid, lock);
+                        dump_stack();
+                }
+        }
+}
+#endif
+
+void do_raw_read_lock(rwlock_t *lock)
+{
+        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+        arch_read_lock(&lock->raw_lock);
+}
+
+int do_raw_read_trylock(rwlock_t *lock)
+{
+        int ret = arch_read_trylock(&lock->raw_lock);
+
+#ifndef CONFIG_SMP
+        /*
+         * Must not happen on UP:
+         */
+        RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+        return ret;
+}
+
+void do_raw_read_unlock(rwlock_t *lock)
+{
+        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+        arch_read_unlock(&lock->raw_lock);
+}
+
+static inline void debug_write_lock_before(rwlock_t *lock)
+{
+        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+        RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
+        RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+                                                        lock, "cpu recursion");
+}
+
+static inline void debug_write_lock_after(rwlock_t *lock)
+{
+        lock->owner_cpu = raw_smp_processor_id();
+        lock->owner = current;
+}
+
+static inline void debug_write_unlock(rwlock_t *lock)
+{
+        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+        RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
+        RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+                                                        lock, "wrong CPU");
+        lock->owner = SPINLOCK_OWNER_INIT;
+        lock->owner_cpu = -1;
+}
+
+#if 0           /* This can cause lockups */
+static void __write_lock_debug(rwlock_t *lock)
+{
+        u64 i;
+        u64 loops = loops_per_jiffy * HZ;
+        int print_once = 1;
+
+        for (;;) {
+                for (i = 0; i < loops; i++) {
+                        if (arch_write_trylock(&lock->raw_lock))
+                                return;
+                        __delay(1);
+                }
+                /* lockup suspected: */
+                if (print_once) {
+                        print_once = 0;
+                        printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
+                                        "%s/%d, %p\n",
+                                raw_smp_processor_id(), current->comm,
+                                current->pid, lock);
+                        dump_stack();
+                }
+        }
+}
+#endif
+
+void do_raw_write_lock(rwlock_t *lock)
+{
+        debug_write_lock_before(lock);
+        arch_write_lock(&lock->raw_lock);
+        debug_write_lock_after(lock);
+}
+
+int do_raw_write_trylock(rwlock_t *lock)
+{
+        int ret = arch_write_trylock(&lock->raw_lock);
+
+        if (ret)
+                debug_write_lock_after(lock);
+#ifndef CONFIG_SMP
+        /*
+         * Must not happen on UP:
+         */
+        RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+        return ret;
+}
+
+void do_raw_write_unlock(rwlock_t *lock)
+{
+        debug_write_unlock(lock);
+        arch_write_unlock(&lock->raw_lock);
+}