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/gfp.h b/include/linux/gfp.h
index 9b4dd49..0437439 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -1,6 +1,7 @@
#ifndef __LINUX_GFP_H
#define __LINUX_GFP_H
+#include <linux/mmdebug.h>
#include <linux/mmzone.h>
#include <linux/stddef.h>
#include <linux/linkage.h>
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d01cc97..8c43cc4 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -2,6 +2,7 @@
#define _LINUX_HUGETLB_H
#include <linux/mm_types.h>
+#include <linux/mmdebug.h>
#include <linux/fs.h>
#include <linux/hugetlb_inline.h>
#include <linux/cgroup.h>
@@ -354,7 +355,7 @@
static inline struct hstate *page_hstate(struct page *page)
{
- VM_BUG_ON(!PageHuge(page));
+ VM_BUG_ON_PAGE(!PageHuge(page), page);
return size_to_hstate(PAGE_SIZE << compound_order(page));
}
diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index ce8217f..787bba3 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -15,6 +15,7 @@
#ifndef _LINUX_HUGETLB_CGROUP_H
#define _LINUX_HUGETLB_CGROUP_H
+#include <linux/mmdebug.h>
#include <linux/res_counter.h>
struct hugetlb_cgroup;
@@ -28,7 +29,7 @@
static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
{
- VM_BUG_ON(!PageHuge(page));
+ VM_BUG_ON_PAGE(!PageHuge(page), page);
if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
return NULL;
@@ -38,7 +39,7 @@
static inline
int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
{
- VM_BUG_ON(!PageHuge(page));
+ VM_BUG_ON_PAGE(!PageHuge(page), page);
if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
return -1;
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,
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 580bd58..5042c03 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -1,10 +1,19 @@
#ifndef LINUX_MM_DEBUG_H
#define LINUX_MM_DEBUG_H 1
+struct page;
+
+extern void dump_page(struct page *page, char *reason);
+extern void dump_page_badflags(struct page *page, char *reason,
+ unsigned long badflags);
+
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
+#define VM_BUG_ON_PAGE(cond, page) \
+ do { if (unlikely(cond)) { dump_page(page, NULL); BUG(); } } while (0)
#else
#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
+#define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 98ada58..e464b4e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -412,7 +412,7 @@
*/
static inline int PageTransHuge(struct page *page)
{
- VM_BUG_ON(PageTail(page));
+ VM_BUG_ON_PAGE(PageTail(page), page);
return PageHead(page);
}
@@ -460,25 +460,25 @@
*/
static inline int PageSlabPfmemalloc(struct page *page)
{
- VM_BUG_ON(!PageSlab(page));
+ VM_BUG_ON_PAGE(!PageSlab(page), page);
return PageActive(page);
}
static inline void SetPageSlabPfmemalloc(struct page *page)
{
- VM_BUG_ON(!PageSlab(page));
+ VM_BUG_ON_PAGE(!PageSlab(page), page);
SetPageActive(page);
}
static inline void __ClearPageSlabPfmemalloc(struct page *page)
{
- VM_BUG_ON(!PageSlab(page));
+ VM_BUG_ON_PAGE(!PageSlab(page), page);
__ClearPageActive(page);
}
static inline void ClearPageSlabPfmemalloc(struct page *page)
{
- VM_BUG_ON(!PageSlab(page));
+ VM_BUG_ON_PAGE(!PageSlab(page), page);
ClearPageActive(page);
}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e3dea75..1710d1b 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -162,7 +162,7 @@
* disabling preempt, and hence no need for the "speculative get" that
* SMP requires.
*/
- VM_BUG_ON(page_count(page) == 0);
+ VM_BUG_ON_PAGE(page_count(page) == 0, page);
atomic_inc(&page->_count);
#else
@@ -175,7 +175,7 @@
return 0;
}
#endif
- VM_BUG_ON(PageTail(page));
+ VM_BUG_ON_PAGE(PageTail(page), page);
return 1;
}
@@ -191,14 +191,14 @@
# ifdef CONFIG_PREEMPT_COUNT
VM_BUG_ON(!in_atomic());
# endif
- VM_BUG_ON(page_count(page) == 0);
+ VM_BUG_ON_PAGE(page_count(page) == 0, page);
atomic_add(count, &page->_count);
#else
if (unlikely(!atomic_add_unless(&page->_count, count, 0)))
return 0;
#endif
- VM_BUG_ON(PageCompound(page) && page != compound_head(page));
+ VM_BUG_ON_PAGE(PageCompound(page) && page != compound_head(page), page);
return 1;
}
@@ -210,7 +210,7 @@
static inline void page_unfreeze_refs(struct page *page, int count)
{
- VM_BUG_ON(page_count(page) != 0);
+ VM_BUG_ON_PAGE(page_count(page) != 0, page);
VM_BUG_ON(count == 0);
atomic_set(&page->_count, count);
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 9e4761c..e3817d2 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -1,6 +1,7 @@
#ifndef __LINUX_PERCPU_H
#define __LINUX_PERCPU_H
+#include <linux/mmdebug.h>
#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/cpumask.h>