mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE

Most of the VM_BUG_ON assertions are performed on a page.  Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.

I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.

This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.

[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/mm/page_io.c b/mm/page_io.c
index 8c79a4764be0..7247be6114ac 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -320,8 +320,8 @@ int swap_readpage(struct page *page)
         int ret = 0;
         struct swap_info_struct *sis = page_swap_info(page);
 
-        VM_BUG_ON(!PageLocked(page));
-        VM_BUG_ON(PageUptodate(page));
+        VM_BUG_ON_PAGE(!PageLocked(page), page);
+        VM_BUG_ON_PAGE(PageUptodate(page), page);
         if (frontswap_load(page) == 0) {
                 SetPageUptodate(page);
                 unlock_page(page);