Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot beembedded to struct page
From: Kirill A. Shutemov
Date: Wed Nov 20 2013 - 07:53:34 EST
Andrey Wagin wrote:
> Hi Kirill,
>
> Looks like this patch adds memory leaks.
> [ 116.188310] kmemleak: 15672 new suspected memory leaks (see
> /sys/kernel/debug/kmemleak)
> unreferenced object 0xffff8800da45a350 (size 96):
> comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
> hex dump (first 32 bytes):
> 07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b .....N......kkkk
> ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff .........$......
> backtrace:
> [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
> [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
> [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
> [<ffffffff81192849>] __pmd_alloc+0x59/0x170
> [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
> [<ffffffff8105a013>] dup_mm+0x313/0x540
> [<ffffffff8105b9da>] copy_process+0x161a/0x1880
> [<ffffffff8105c01b>] do_fork+0x8b/0x360
> [<ffffffff8105c306>] SyS_clone+0x16/0x20
> [<ffffffff81727b79>] stub_clone+0x69/0x90
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> It's quite serious, because my test host went to panic in a few hours.
Sorry for that.
Could you test patch below.
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index a7cccb6d7fec..7be5809754cf 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -61,6 +61,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
#if PAGETABLE_LEVELS > 2
void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
{
+ struct page *page = virt_to_page(pmd);
paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
/*
* NOTE! For PAE, any changes to the top page-directory-pointer-table
@@ -69,7 +70,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
#ifdef CONFIG_X86_PAE
tlb->need_flush_all = 1;
#endif
- tlb_remove_page(tlb, virt_to_page(pmd));
+ pgtable_pmd_page_dtor(page);
+ tlb_remove_page(tlb, page);
}
#if PAGETABLE_LEVELS > 3
--
Kirill A. Shutemov
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