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>
diff --git a/mm/internal.h b/mm/internal.h
index a346ba1..dc95e97 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -27,8 +27,8 @@
*/
static inline void set_page_refcounted(struct page *page)
{
- VM_BUG_ON(PageTail(page));
- VM_BUG_ON(atomic_read(&page->_count));
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count), page);
set_page_count(page, 1);
}
@@ -46,7 +46,7 @@
* speculative page access (like in
* page_cache_get_speculative()) on tail pages.
*/
- VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
+ VM_BUG_ON_PAGE(atomic_read(&page->first_page->_count) <= 0, page);
if (get_page_head)
atomic_inc(&page->first_page->_count);
get_huge_page_tail(page);
@@ -71,7 +71,7 @@
* Getting a normal page or the head of a compound page
* requires to already have an elevated page->_count.
*/
- VM_BUG_ON(atomic_read(&page->_count) <= 0);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
atomic_inc(&page->_count);
}
}
@@ -173,7 +173,7 @@
static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
struct page *page)
{
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
return 0;
