lib/spinlock_debug.c: print owner on spinlock lockup

When SPIN_BUG_ON is triggered, the lock owner information is reported.
But it is omitted when spinlock lockup is detected.

This information is useful especially on the architectures which don't
implement trigger_all_cpu_backtrace() that is called just after detecting
lockup.  So report it and also avoid message format duplication.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 9 deletions

diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index 4755b98b6dfb..5f3eacdd6178 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -49,13 +49,10 @@ void __rwlock_init(rwlock_t *lock, const char *name,
 
 EXPORT_SYMBOL(__rwlock_init);
 
-static void spin_bug(raw_spinlock_t *lock, const char *msg)
+static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
         struct task_struct *owner = NULL;
 
-        if (!debug_locks_off())
-                return;
-
         if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
                 owner = lock->owner;
         printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
@@ -70,6 +67,14 @@ static void spin_bug(raw_spinlock_t *lock, const char *msg)
         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
@@ -113,11 +118,7 @@ static void __spin_lock_debug(raw_spinlock_t *lock)
                 /* lockup suspected: */
                 if (print_once) {
                         print_once = 0;
-                        printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
-                                        "%s/%d, %p\n",
-                                raw_smp_processor_id(), current->comm,
-                                task_pid_nr(current), lock);
-                        dump_stack();
+                        spin_dump(lock, "lockup");
 #ifdef CONFIG_SMP
                         trigger_all_cpu_backtrace();
 #endif