[PATCH] move rmap BUG_ON outside DEBUG_VM

We have a persistent dribble of reports of this BUG triggering.  Its extended
diagnostics were recently made conditional on CONFIG_DEBUG_VM, which was a bad
idea - we want to know about it.

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index e2155d791d99..a9136d8b7577 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -576,15 +576,14 @@ void page_add_file_rmap(struct page *page)
 void page_remove_rmap(struct page *page)
 {
         if (atomic_add_negative(-1, &page->_mapcount)) {
-#ifdef CONFIG_DEBUG_VM
                 if (unlikely(page_mapcount(page) < 0)) {
                         printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
                         printk (KERN_EMERG "  page->flags = %lx\n", page->flags);
                         printk (KERN_EMERG "  page->count = %x\n", page_count(page));
                         printk (KERN_EMERG "  page->mapping = %p\n", page->mapping);
+                        BUG();
                 }
-#endif
-                BUG_ON(page_mapcount(page) < 0);
+
                 /*
                  * It would be tidy to reset the PageAnon mapping here,
                  * but that might overwrite a racing page_add_anon_rmap