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>

1 files changed, 14 insertions, 14 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7890ce9d6bd1..72f2d90e7ef6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2897,7 +2897,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 	unsigned short id;
 	swp_entry_t ent;
 
-	VM_BUG_ON(!PageLocked(page));
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
 
 	pc = lookup_page_cgroup(page);
 	lock_page_cgroup(pc);
@@ -2931,7 +2931,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
 	bool anon;
 
 	lock_page_cgroup(pc);
-	VM_BUG_ON(PageCgroupUsed(pc));
+	VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
 	/*
 	 * we don't need page_cgroup_lock about tail pages, becase they are not
 	 * accessed by any other context at this point.
@@ -2966,7 +2966,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
 	if (lrucare) {
 		if (was_on_lru) {
 			lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
-			VM_BUG_ON(PageLRU(page));
+			VM_BUG_ON_PAGE(PageLRU(page), page);
 			SetPageLRU(page);
 			add_page_to_lru_list(page, lruvec, page_lru(page));
 		}
@@ -3780,7 +3780,7 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order)
 	if (!memcg)
 		return;
 
-	VM_BUG_ON(mem_cgroup_is_root(memcg));
+	VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
 	memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
 }
 #else
@@ -3859,7 +3859,7 @@ static int mem_cgroup_move_account(struct page *page,
 	bool anon = PageAnon(page);
 
 	VM_BUG_ON(from == to);
-	VM_BUG_ON(PageLRU(page));
+	VM_BUG_ON_PAGE(PageLRU(page), page);
 	/*
 	 * The page is isolated from LRU. So, collapse function
 	 * will not handle this page. But page splitting can happen.
@@ -3952,7 +3952,7 @@ static int mem_cgroup_move_parent(struct page *page,
 		parent = root_mem_cgroup;
 
 	if (nr_pages > 1) {
-		VM_BUG_ON(!PageTransHuge(page));
+		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 		flags = compound_lock_irqsave(page);
 	}
 
@@ -3986,7 +3986,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
 
 	if (PageTransHuge(page)) {
 		nr_pages <<= compound_order(page);
-		VM_BUG_ON(!PageTransHuge(page));
+		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 		/*
 		 * Never OOM-kill a process for a huge page.  The
 		 * fault handler will fall back to regular pages.
@@ -4006,8 +4006,8 @@ int mem_cgroup_newpage_charge(struct page *page,
 {
 	if (mem_cgroup_disabled())
 		return 0;
-	VM_BUG_ON(page_mapped(page));
-	VM_BUG_ON(page->mapping && !PageAnon(page));
+	VM_BUG_ON_PAGE(page_mapped(page), page);
+	VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
 	VM_BUG_ON(!mm);
 	return mem_cgroup_charge_common(page, mm, gfp_mask,
 					MEM_CGROUP_CHARGE_TYPE_ANON);
@@ -4211,7 +4211,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
 
 	if (PageTransHuge(page)) {
 		nr_pages <<= compound_order(page);
-		VM_BUG_ON(!PageTransHuge(page));
+		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 	}
 	/*
 	 * Check if our page_cgroup is valid
@@ -4303,7 +4303,7 @@ void mem_cgroup_uncharge_page(struct page *page)
 	/* early check. */
 	if (page_mapped(page))
 		return;
-	VM_BUG_ON(page->mapping && !PageAnon(page));
+	VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
 	/*
 	 * If the page is in swap cache, uncharge should be deferred
 	 * to the swap path, which also properly accounts swap usage
@@ -4323,8 +4323,8 @@ void mem_cgroup_uncharge_page(struct page *page)
 
 void mem_cgroup_uncharge_cache_page(struct page *page)
 {
-	VM_BUG_ON(page_mapped(page));
-	VM_BUG_ON(page->mapping);
+	VM_BUG_ON_PAGE(page_mapped(page), page);
+	VM_BUG_ON_PAGE(page->mapping, page);
 	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
 }
 
@@ -6880,7 +6880,7 @@ static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
 	enum mc_target_type ret = MC_TARGET_NONE;
 
 	page = pmd_page(pmd);
-	VM_BUG_ON(!page || !PageHead(page));
+	VM_BUG_ON_PAGE(!page || !PageHead(page), page);
 	if (!move_anon())
 		return ret;
 	pc = lookup_page_cgroup(page);