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/mlock.c b/mm/mlock.c
index b30adbe62034..4e1a68162285 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -279,8 +279,8 @@ static int __mlock_posix_error_return(long retval)
 static bool __putback_lru_fast_prepare(struct page *page, struct pagevec *pvec,
                 int *pgrescued)
 {
-        VM_BUG_ON(PageLRU(page));
-        VM_BUG_ON(!PageLocked(page));
+        VM_BUG_ON_PAGE(PageLRU(page), page);
+        VM_BUG_ON_PAGE(!PageLocked(page), page);
 
         if (page_mapcount(page) <= 1 && page_evictable(page)) {
                 pagevec_add(pvec, page);