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, 18 insertions, 18 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 95d1acb0f3d..25fab7150fa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -712,7 +712,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 	pgtable_t pgtable;
 	spinlock_t *ptl;
 
-	VM_BUG_ON(!PageCompound(page));
+	VM_BUG_ON_PAGE(!PageCompound(page), page);
 	pgtable = pte_alloc_one(mm, haddr);
 	if (unlikely(!pgtable))
 		return VM_FAULT_OOM;
@@ -893,7 +893,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		goto out;
 	}
 	src_page = pmd_page(pmd);
-	VM_BUG_ON(!PageHead(src_page));
+	VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
 	get_page(src_page);
 	page_dup_rmap(src_page);
 	add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
@@ -1067,7 +1067,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 	ptl = pmd_lock(mm, pmd);
 	if (unlikely(!pmd_same(*pmd, orig_pmd)))
 		goto out_free_pages;
-	VM_BUG_ON(!PageHead(page));
+	VM_BUG_ON_PAGE(!PageHead(page), page);
 
 	pmdp_clear_flush(vma, haddr, pmd);
 	/* leave pmd empty until pte is filled */
@@ -1133,7 +1133,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		goto out_unlock;
 
 	page = pmd_page(orig_pmd);
-	VM_BUG_ON(!PageCompound(page) || !PageHead(page));
+	VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page);
 	if (page_mapcount(page) == 1) {
 		pmd_t entry;
 		entry = pmd_mkyoung(orig_pmd);
@@ -1211,7 +1211,7 @@ alloc:
 			add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
 			put_huge_zero_page();
 		} else {
-			VM_BUG_ON(!PageHead(page));
+			VM_BUG_ON_PAGE(!PageHead(page), page);
 			page_remove_rmap(page);
 			put_page(page);
 		}
@@ -1249,7 +1249,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 		goto out;
 
 	page = pmd_page(*pmd);
-	VM_BUG_ON(!PageHead(page));
+	VM_BUG_ON_PAGE(!PageHead(page), page);
 	if (flags & FOLL_TOUCH) {
 		pmd_t _pmd;
 		/*
@@ -1274,7 +1274,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 		}
 	}
 	page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
-	VM_BUG_ON(!PageCompound(page));
+	VM_BUG_ON_PAGE(!PageCompound(page), page);
 	if (flags & FOLL_GET)
 		get_page_foll(page);
 
@@ -1432,9 +1432,9 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		} else {
 			page = pmd_page(orig_pmd);
 			page_remove_rmap(page);
-			VM_BUG_ON(page_mapcount(page) < 0);
+			VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
 			add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
-			VM_BUG_ON(!PageHead(page));
+			VM_BUG_ON_PAGE(!PageHead(page), page);
 			atomic_long_dec(&tlb->mm->nr_ptes);
 			spin_unlock(ptl);
 			tlb_remove_page(tlb, page);
@@ -2176,9 +2176,9 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
 		if (unlikely(!page))
 			goto out;
 
-		VM_BUG_ON(PageCompound(page));
-		BUG_ON(!PageAnon(page));
-		VM_BUG_ON(!PageSwapBacked(page));
+		VM_BUG_ON_PAGE(PageCompound(page), page);
+		VM_BUG_ON_PAGE(!PageAnon(page), page);
+		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
 
 		/* cannot use mapcount: can't collapse if there's a gup pin */
 		if (page_count(page) != 1)
@@ -2201,8 +2201,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
 		}
 		/* 0 stands for page_is_file_cache(page) == false */
 		inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
-		VM_BUG_ON(!PageLocked(page));
-		VM_BUG_ON(PageLRU(page));
+		VM_BUG_ON_PAGE(!PageLocked(page), page);
+		VM_BUG_ON_PAGE(PageLRU(page), page);
 
 		/* If there is no mapped pte young don't collapse the page */
 		if (pte_young(pteval) || PageReferenced(page) ||
@@ -2232,7 +2232,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
 		} else {
 			src_page = pte_page(pteval);
 			copy_user_highpage(page, src_page, address, vma);
-			VM_BUG_ON(page_mapcount(src_page) != 1);
+			VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page);
 			release_pte_page(src_page);
 			/*
 			 * ptl mostly unnecessary, but preempt has to
@@ -2311,7 +2311,7 @@ static struct page
 		       struct vm_area_struct *vma, unsigned long address,
 		       int node)
 {
-	VM_BUG_ON(*hpage);
+	VM_BUG_ON_PAGE(*hpage, *hpage);
 	/*
 	 * Allocate the page while the vma is still valid and under
 	 * the mmap_sem read mode so there is no memory allocation
@@ -2580,7 +2580,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 		 */
 		node = page_to_nid(page);
 		khugepaged_node_load[node]++;
-		VM_BUG_ON(PageCompound(page));
+		VM_BUG_ON_PAGE(PageCompound(page), page);
 		if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
 			goto out_unmap;
 		/* cannot use mapcount: can't collapse if there's a gup pin */
@@ -2876,7 +2876,7 @@ again:
 		return;
 	}
 	page = pmd_page(*pmd);
-	VM_BUG_ON(!page_count(page));
+	VM_BUG_ON_PAGE(!page_count(page), page);
 	get_page(page);
 	spin_unlock(ptl);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);