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/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 0596e8e..207d9aef 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -108,8 +108,8 @@
static inline void get_head_page_multiple(struct page *page, int nr)
{
- VM_BUG_ON(page != compound_head(page));
- VM_BUG_ON(page_count(page) == 0);
+ VM_BUG_ON_PAGE(page != compound_head(page), page);
+ VM_BUG_ON_PAGE(page_count(page) == 0, page);
atomic_add(nr, &page->_count);
SetPageReferenced(page);
}
@@ -135,7 +135,7 @@
head = pte_page(pte);
page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
do {
- VM_BUG_ON(compound_head(page) != head);
+ VM_BUG_ON_PAGE(compound_head(page) != head, page);
pages[*nr] = page;
if (PageTail(page))
get_huge_page_tail(page);
@@ -212,7 +212,7 @@
head = pte_page(pte);
page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
do {
- VM_BUG_ON(compound_head(page) != head);
+ VM_BUG_ON_PAGE(compound_head(page) != head, page);
pages[*nr] = page;
if (PageTail(page))
get_huge_page_tail(page);