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, 6 insertions, 6 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 545a170..34bb8c6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1559,7 +1559,7 @@ static inline void *acquire_slab(struct kmem_cache *s,
 		new.freelist = freelist;
 	}
 
-	VM_BUG_ON(new.frozen);
+	VM_BUG_ON_PAGE(new.frozen, &new);
 	new.frozen = 1;
 
 	if (!__cmpxchg_double_slab(s, page,
@@ -1812,7 +1812,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 			set_freepointer(s, freelist, prior);
 			new.counters = counters;
 			new.inuse--;
-			VM_BUG_ON(!new.frozen);
+			VM_BUG_ON_PAGE(!new.frozen, &new);
 
 		} while (!__cmpxchg_double_slab(s, page,
 			prior, counters,
@@ -1840,7 +1840,7 @@ redo:
 
 	old.freelist = page->freelist;
 	old.counters = page->counters;
-	VM_BUG_ON(!old.frozen);
+	VM_BUG_ON_PAGE(!old.frozen, &old);
 
 	/* Determine target state of the slab */
 	new.counters = old.counters;
@@ -1952,7 +1952,7 @@ static void unfreeze_partials(struct kmem_cache *s,
 
 			old.freelist = page->freelist;
 			old.counters = page->counters;
-			VM_BUG_ON(!old.frozen);
+			VM_BUG_ON_PAGE(!old.frozen, &old);
 
 			new.counters = old.counters;
 			new.freelist = old.freelist;
@@ -2225,7 +2225,7 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page)
 		counters = page->counters;
 
 		new.counters = counters;
-		VM_BUG_ON(!new.frozen);
+		VM_BUG_ON_PAGE(!new.frozen, &new);
 
 		new.inuse = page->objects;
 		new.frozen = freelist != NULL;
@@ -2319,7 +2319,7 @@ load_freelist:
 	 * page is pointing to the page from which the objects are obtained.
 	 * That page must be frozen for per cpu allocations to work.
 	 */
-	VM_BUG_ON(!c->page->frozen);
+	VM_BUG_ON_PAGE(!c->page->frozen, c->page);
 	c->freelist = get_freepointer(s, freelist);
 	c->tid = next_tid(c->tid);
 	local_irq_restore(flags);