Merge commit v3.13-rc1 into kbuild/misc

1 files changed, 187 insertions, 0 deletions

diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
new file mode 100644
index 000000000000..13b243a323fa
--- /dev/null
+++ b/kernel/locking/rtmutex-debug.c
@@ -0,0 +1,187 @@
+/*
+ * RT-Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This code is based on the rt.c implementation in the preempt-rt tree.
+ * Portions of said code are
+ *
+ *  Copyright (C) 2004  LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ *  Copyright (C) 2006  Esben Nielsen
+ *  Copyright (C) 2006  Kihon Technologies Inc.,
+ *                      Steven Rostedt <rostedt@goodmis.org>
+ *
+ * See rt.c in preempt-rt for proper credits and further information
+ */
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/plist.h>
+#include <linux/fs.h>
+#include <linux/debug_locks.h>
+
+#include "rtmutex_common.h"
+
+static void printk_task(struct task_struct *p)
+{
+        if (p)
+                printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
+        else
+                printk("<none>");
+}
+
+static void printk_lock(struct rt_mutex *lock, int print_owner)
+{
+        if (lock->name)
+                printk(" [%p] {%s}\n",
+                        lock, lock->name);
+        else
+                printk(" [%p] {%s:%d}\n",
+                        lock, lock->file, lock->line);
+
+        if (print_owner && rt_mutex_owner(lock)) {
+                printk(".. ->owner: %p\n", lock->owner);
+                printk(".. held by:  ");
+                printk_task(rt_mutex_owner(lock));
+                printk("\n");
+        }
+}
+
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+        DEBUG_LOCKS_WARN_ON(!plist_head_empty(&task->pi_waiters));
+        DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+
+/*
+ * We fill out the fields in the waiter to store the information about
+ * the deadlock. We print when we return. act_waiter can be NULL in
+ * case of a remove waiter operation.
+ */
+void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
+                             struct rt_mutex *lock)
+{
+        struct task_struct *task;
+
+        if (!debug_locks || detect || !act_waiter)
+                return;
+
+        task = rt_mutex_owner(act_waiter->lock);
+        if (task && task != current) {
+                act_waiter->deadlock_task_pid = get_pid(task_pid(task));
+                act_waiter->deadlock_lock = lock;
+        }
+}
+
+void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
+{
+        struct task_struct *task;
+
+        if (!waiter->deadlock_lock || !debug_locks)
+                return;
+
+        rcu_read_lock();
+        task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
+        if (!task) {
+                rcu_read_unlock();
+                return;
+        }
+
+        if (!debug_locks_off()) {
+                rcu_read_unlock();
+                return;
+        }
+
+        printk("\n============================================\n");
+        printk(  "[ BUG: circular locking deadlock detected! ]\n");
+        printk("%s\n", print_tainted());
+        printk(  "--------------------------------------------\n");
+        printk("%s/%d is deadlocking current task %s/%d\n\n",
+               task->comm, task_pid_nr(task),
+               current->comm, task_pid_nr(current));
+
+        printk("\n1) %s/%d is trying to acquire this lock:\n",
+               current->comm, task_pid_nr(current));
+        printk_lock(waiter->lock, 1);
+
+        printk("\n2) %s/%d is blocked on this lock:\n",
+                task->comm, task_pid_nr(task));
+        printk_lock(waiter->deadlock_lock, 1);
+
+        debug_show_held_locks(current);
+        debug_show_held_locks(task);
+
+        printk("\n%s/%d's [blocked] stackdump:\n\n",
+                task->comm, task_pid_nr(task));
+        show_stack(task, NULL);
+        printk("\n%s/%d's [current] stackdump:\n\n",
+                current->comm, task_pid_nr(current));
+        dump_stack();
+        debug_show_all_locks();
+        rcu_read_unlock();
+
+        printk("[ turning off deadlock detection."
+               "Please report this trace. ]\n\n");
+}
+
+void debug_rt_mutex_lock(struct rt_mutex *lock)
+{
+}
+
+void debug_rt_mutex_unlock(struct rt_mutex *lock)
+{
+        DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
+}
+
+void
+debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
+{
+}
+
+void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+{
+        DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
+}
+
+void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+        memset(waiter, 0x11, sizeof(*waiter));
+        plist_node_init(&waiter->list_entry, MAX_PRIO);
+        plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
+        waiter->deadlock_task_pid = NULL;
+}
+
+void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+{
+        put_pid(waiter->deadlock_task_pid);
+        DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->list_entry));
+        DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
+        memset(waiter, 0x22, sizeof(*waiter));
+}
+
+void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
+{
+        /*
+         * Make sure we are not reinitializing a held lock:
+         */
+        debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+        lock->name = name;
+}
+
+void
+rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task)
+{
+}
+
+void rt_mutex_deadlock_account_unlock(struct task_struct *task)
+{
+}
+