From 309381feaee564281c3d9e90fbca8963bb7428ad Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Thu, 23 Jan 2014 15:52:54 -0800 Subject: 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 Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/internal.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'mm/internal.h') diff --git a/mm/internal.h b/mm/internal.h index a346ba120e42..dc95e979ae56 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -27,8 +27,8 @@ static inline void set_page_count(struct page *page, int v) */ 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 @@ static inline void __get_page_tail_foll(struct page *page, * 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 @@ static inline void get_page_foll(struct page *page) * 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 void munlock_vma_pages_all(struct vm_area_struct *vma) 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; -- cgit v1.2.3-55-g7522