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mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE

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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>
This commit is contained in:
Sasha Levin
2014-01-23 15:52:54 -08:00
committed by Linus Torvalds
parent e3bba3c3c9
commit 309381feae
30 changed files with 181 additions and 170 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
mm/huge_memory.c
View File

@@ -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);