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/swap.c b/mm/swap.c
index d1100b6..b31ba67 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -57,7 +57,7 @@
spin_lock_irqsave(&zone->lru_lock, flags);
lruvec = mem_cgroup_page_lruvec(page, zone);
- VM_BUG_ON(!PageLRU(page));
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(&zone->lru_lock, flags);
@@ -130,8 +130,8 @@
* __split_huge_page_refcount cannot race
* here.
*/
- VM_BUG_ON(!PageHead(page_head));
- VM_BUG_ON(page_mapcount(page) != 0);
+ VM_BUG_ON_PAGE(!PageHead(page_head), page_head);
+ VM_BUG_ON_PAGE(page_mapcount(page) != 0, page);
if (put_page_testzero(page_head)) {
/*
* If this is the tail of a slab
@@ -148,7 +148,7 @@
* the compound page enters the buddy
* allocator.
*/
- VM_BUG_ON(PageSlab(page_head));
+ VM_BUG_ON_PAGE(PageSlab(page_head), page_head);
__put_compound_page(page_head);
}
return;
@@ -199,7 +199,7 @@
__put_single_page(page);
return;
}
- VM_BUG_ON(page_head != page->first_page);
+ VM_BUG_ON_PAGE(page_head != page->first_page, page);
/*
* We can release the refcount taken by
* get_page_unless_zero() now that
@@ -207,12 +207,12 @@
* compound_lock.
*/
if (put_page_testzero(page_head))
- VM_BUG_ON(1);
+ VM_BUG_ON_PAGE(1, page_head);
/* __split_huge_page_refcount will wait now */
- VM_BUG_ON(page_mapcount(page) <= 0);
+ VM_BUG_ON_PAGE(page_mapcount(page) <= 0, page);
atomic_dec(&page->_mapcount);
- VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
- VM_BUG_ON(atomic_read(&page->_count) != 0);
+ VM_BUG_ON_PAGE(atomic_read(&page_head->_count) <= 0, page_head);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
compound_unlock_irqrestore(page_head, flags);
if (put_page_testzero(page_head)) {
@@ -223,7 +223,7 @@
}
} else {
/* page_head is a dangling pointer */
- VM_BUG_ON(PageTail(page));
+ VM_BUG_ON_PAGE(PageTail(page), page);
goto out_put_single;
}
}
@@ -264,7 +264,7 @@
* page. __split_huge_page_refcount
* cannot race here.
*/
- VM_BUG_ON(!PageHead(page_head));
+ VM_BUG_ON_PAGE(!PageHead(page_head), page_head);
__get_page_tail_foll(page, true);
return true;
} else {
@@ -604,8 +604,8 @@
*/
void lru_cache_add(struct page *page)
{
- VM_BUG_ON(PageActive(page) && PageUnevictable(page));
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
+ VM_BUG_ON_PAGE(PageLRU(page), page);
__lru_cache_add(page);
}
@@ -846,7 +846,7 @@
}
lruvec = mem_cgroup_page_lruvec(page, zone);
- VM_BUG_ON(!PageLRU(page));
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}
@@ -888,9 +888,9 @@
{
const int file = 0;
- VM_BUG_ON(!PageHead(page));
- VM_BUG_ON(PageCompound(page_tail));
- VM_BUG_ON(PageLRU(page_tail));
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ VM_BUG_ON_PAGE(PageCompound(page_tail), page);
+ VM_BUG_ON_PAGE(PageLRU(page_tail), page);
VM_BUG_ON(NR_CPUS != 1 &&
!spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
@@ -929,7 +929,7 @@
int active = PageActive(page);
enum lru_list lru = page_lru(page);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, lru);