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/huge_memory.c b/mm/huge_memory.c
index 95d1acb..25fab71 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -712,7 +712,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
}
}
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 @@
} 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 @@
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 @@
}
/* 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 @@
} 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 @@
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 @@
*/
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 @@
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);