[PATCH] fix spinlock-debugging smp_processor_id() usage

When a spinlock debugging check hits, we print the CPU number as an
informational thing - but there is no guarantee that preemption is off
at that point - hence we should use raw_smp_processor_id().  Otherwise
DEBUG_PREEMPT will print a warning.

With this fix the warning goes away and only the spinlock-debugging info
is printed.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index 906ad10..dcd4be9 100644 (file)
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -20,7 +20,8 @@ static void spin_bug(spinlock_t *lock, const char *msg)
                if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
                        owner = lock->owner;
                printk("BUG: spinlock %s on CPU#%d, %s/%d\n",
-                       msg, smp_processor_id(), current->comm, current->pid);
+                       msg, raw_smp_processor_id(),
+                       current->comm, current->pid);
                printk(" lock: %p, .magic: %08x, .owner: %s/%d, .owner_cpu: %d\n",
                        lock, lock->magic,
                        owner ? owner->comm : "<none>",
@@ -78,8 +79,8 @@ static void __spin_lock_debug(spinlock_t *lock)
                if (print_once) {
                        print_once = 0;
                        printk("BUG: spinlock lockup on CPU#%d, %s/%d, %p\n",
-                               smp_processor_id(), current->comm, current->pid,
-                                       lock);
+                               raw_smp_processor_id(), current->comm,
+                               current->pid, lock);
                        dump_stack();
                }
        }
@@ -120,7 +121,8 @@ static void rwlock_bug(rwlock_t *lock, const char *msg)
 
        if (xchg(&print_once, 0)) {
                printk("BUG: rwlock %s on CPU#%d, %s/%d, %p\n", msg,
-                       smp_processor_id(), current->comm, current->pid, lock);
+                       raw_smp_processor_id(), current->comm,
+                       current->pid, lock);
                dump_stack();
 #ifdef CONFIG_SMP
                /*
@@ -148,8 +150,8 @@ static void __read_lock_debug(rwlock_t *lock)
                if (print_once) {
                        print_once = 0;
                        printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n",
-                               smp_processor_id(), current->comm, current->pid,
-                                       lock);
+                               raw_smp_processor_id(), current->comm,
+                               current->pid, lock);
                        dump_stack();
                }
        }
@@ -220,8 +222,8 @@ static void __write_lock_debug(rwlock_t *lock)
                if (print_once) {
                        print_once = 0;
                        printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n",
-                               smp_processor_id(), current->comm, current->pid,
-                                       lock);
+                               raw_smp_processor_id(), current->comm,
+                               current->pid, lock);
                        dump_stack();
                }
        }