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/include/linux/mm.h b/include/linux/mm.h
index 03bbcb8..d9992fc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5,6 +5,7 @@
#ifdef __KERNEL__
+#include <linux/mmdebug.h>
#include <linux/gfp.h>
#include <linux/bug.h>
#include <linux/list.h>
@@ -303,7 +304,7 @@
*/
static inline int put_page_testzero(struct page *page)
{
- VM_BUG_ON(atomic_read(&page->_count) == 0);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0, page);
return atomic_dec_and_test(&page->_count);
}
@@ -364,7 +365,7 @@
static inline void compound_lock(struct page *page)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- VM_BUG_ON(PageSlab(page));
+ VM_BUG_ON_PAGE(PageSlab(page), page);
bit_spin_lock(PG_compound_lock, &page->flags);
#endif
}
@@ -372,7 +373,7 @@
static inline void compound_unlock(struct page *page)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- VM_BUG_ON(PageSlab(page));
+ VM_BUG_ON_PAGE(PageSlab(page), page);
bit_spin_unlock(PG_compound_lock, &page->flags);
#endif
}
@@ -447,7 +448,7 @@
*/
static inline bool compound_tail_refcounted(struct page *page)
{
- VM_BUG_ON(!PageHead(page));
+ VM_BUG_ON_PAGE(!PageHead(page), page);
return __compound_tail_refcounted(page);
}
@@ -456,9 +457,9 @@
/*
* __split_huge_page_refcount() cannot run from under us.
*/
- VM_BUG_ON(!PageTail(page));
- VM_BUG_ON(page_mapcount(page) < 0);
- VM_BUG_ON(atomic_read(&page->_count) != 0);
+ VM_BUG_ON_PAGE(!PageTail(page), page);
+ VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
if (compound_tail_refcounted(page->first_page))
atomic_inc(&page->_mapcount);
}
@@ -474,7 +475,7 @@
* 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);
}
@@ -511,13 +512,13 @@
static inline void __SetPageBuddy(struct page *page)
{
- VM_BUG_ON(atomic_read(&page->_mapcount) != -1);
+ VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
}
static inline void __ClearPageBuddy(struct page *page)
{
- VM_BUG_ON(!PageBuddy(page));
+ VM_BUG_ON_PAGE(!PageBuddy(page), page);
atomic_set(&page->_mapcount, -1);
}
@@ -1401,7 +1402,7 @@
* slab code uses page->slab_cache and page->first_page (for tail
* pages), which share storage with page->ptl.
*/
- VM_BUG_ON(*(unsigned long *)&page->ptl);
+ VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
if (!ptlock_alloc(page))
return false;
spin_lock_init(ptlock_ptr(page));
@@ -1492,7 +1493,7 @@
static inline void pgtable_pmd_page_dtor(struct page *page)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- VM_BUG_ON(page->pmd_huge_pte);
+ VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
#endif
ptlock_free(page);
}
@@ -2029,10 +2030,6 @@
extern atomic_long_t num_poisoned_pages;
extern int soft_offline_page(struct page *page, int flags);
-extern void dump_page(struct page *page, char *reason);
-extern void dump_page_badflags(struct page *page, char *reason,
- unsigned long badflags);
-
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
extern void clear_huge_page(struct page *page,
unsigned long addr,