[PATCH] iounmap debugging

We get sporadic reports of `__iounmap: bad address' coming out.  Add a
dump_stack() to find the culprit.

Try to identify which subsystem is having iounmap() problems.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
index 6b25afc933b6..f379b8d67558 100644
--- a/arch/i386/mm/ioremap.c
+++ b/arch/i386/mm/ioremap.c
@@ -228,7 +228,8 @@ EXPORT_SYMBOL(ioremap_nocache);
 void iounmap(volatile void __iomem *addr)
 {
         struct vm_struct *p;
-        if ((void __force *) addr <= high_memory) 
+
+        if ((void __force *)addr <= high_memory)
                 return;
 
         /*
@@ -241,9 +242,10 @@ void iounmap(volatile void __iomem *addr)
                 return;
 
         write_lock(&vmlist_lock);
-        p = __remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
+        p = __remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
         if (!p) { 
                 printk(KERN_WARNING "iounmap: bad address %p\n", addr);
+                dump_stack();
                 goto out_unlock;
         }