mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-13 14:04:05 +08:00
99fa8a4820
Patch series "mm/thp: fix THP splitting unmap BUGs and related", v10.
Here is v2 batch of long-standing THP bug fixes that I had not got
around to sending before, but prompted now by Wang Yugui's report
https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Wang Yugui has tested a rollup of these fixes applied to 5.10.39, and
they have done no harm, but have *not* fixed that issue: something more
is needed and I have no idea of what.
This patch (of 7):
Stressing huge tmpfs page migration racing hole punch often crashed on
the VM_BUG_ON(!pmd_present) in pmdp_huge_clear_flush(), with DEBUG_VM=y
kernel; or shortly afterwards, on a bad dereference in
__split_huge_pmd_locked() when DEBUG_VM=n. They forgot to allow for pmd
migration entries in the non-anonymous case.
Full disclosure: those particular experiments were on a kernel with more
relaxed mmap_lock and i_mmap_rwsem locking, and were not repeated on the
vanilla kernel: it is conceivable that stricter locking happens to avoid
those cases, or makes them less likely; but __split_huge_pmd_locked()
already allowed for pmd migration entries when handling anonymous THPs,
so this commit brings the shmem and file THP handling into line.
And while there: use old_pmd rather than _pmd, as in the following
blocks; and make it clearer to the eye that the !vma_is_anonymous()
block is self-contained, making an early return after accounting for
unmapping.
Link: https://lkml.kernel.org/r/af88612-1473-2eaa-903-8d1a448b26@google.com
Link: https://lkml.kernel.org/r/dd221a99-efb3-cd1d-6256-7e646af29314@google.com
Fixes: e71769ae52
("mm: enable thp migration for shmem thp")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jue Wang <juew@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
223 lines
5.6 KiB
C
223 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* mm/pgtable-generic.c
|
|
*
|
|
* Generic pgtable methods declared in linux/pgtable.h
|
|
*
|
|
* Copyright (C) 2010 Linus Torvalds
|
|
*/
|
|
|
|
#include <linux/pagemap.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/pgtable.h>
|
|
#include <asm/tlb.h>
|
|
|
|
/*
|
|
* If a p?d_bad entry is found while walking page tables, report
|
|
* the error, before resetting entry to p?d_none. Usually (but
|
|
* very seldom) called out from the p?d_none_or_clear_bad macros.
|
|
*/
|
|
|
|
void pgd_clear_bad(pgd_t *pgd)
|
|
{
|
|
pgd_ERROR(*pgd);
|
|
pgd_clear(pgd);
|
|
}
|
|
|
|
#ifndef __PAGETABLE_P4D_FOLDED
|
|
void p4d_clear_bad(p4d_t *p4d)
|
|
{
|
|
p4d_ERROR(*p4d);
|
|
p4d_clear(p4d);
|
|
}
|
|
#endif
|
|
|
|
#ifndef __PAGETABLE_PUD_FOLDED
|
|
void pud_clear_bad(pud_t *pud)
|
|
{
|
|
pud_ERROR(*pud);
|
|
pud_clear(pud);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Note that the pmd variant below can't be stub'ed out just as for p4d/pud
|
|
* above. pmd folding is special and typically pmd_* macros refer to upper
|
|
* level even when folded
|
|
*/
|
|
void pmd_clear_bad(pmd_t *pmd)
|
|
{
|
|
pmd_ERROR(*pmd);
|
|
pmd_clear(pmd);
|
|
}
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
|
|
/*
|
|
* Only sets the access flags (dirty, accessed), as well as write
|
|
* permission. Furthermore, we know it always gets set to a "more
|
|
* permissive" setting, which allows most architectures to optimize
|
|
* this. We return whether the PTE actually changed, which in turn
|
|
* instructs the caller to do things like update__mmu_cache. This
|
|
* used to be done in the caller, but sparc needs minor faults to
|
|
* force that call on sun4c so we changed this macro slightly
|
|
*/
|
|
int ptep_set_access_flags(struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep,
|
|
pte_t entry, int dirty)
|
|
{
|
|
int changed = !pte_same(*ptep, entry);
|
|
if (changed) {
|
|
set_pte_at(vma->vm_mm, address, ptep, entry);
|
|
flush_tlb_fix_spurious_fault(vma, address);
|
|
}
|
|
return changed;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
|
|
int ptep_clear_flush_young(struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep)
|
|
{
|
|
int young;
|
|
young = ptep_test_and_clear_young(vma, address, ptep);
|
|
if (young)
|
|
flush_tlb_page(vma, address);
|
|
return young;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
|
|
pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pte_t *ptep)
|
|
{
|
|
struct mm_struct *mm = (vma)->vm_mm;
|
|
pte_t pte;
|
|
pte = ptep_get_and_clear(mm, address, ptep);
|
|
if (pte_accessible(mm, pte))
|
|
flush_tlb_page(vma, address);
|
|
return pte;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
|
|
int pmdp_set_access_flags(struct vm_area_struct *vma,
|
|
unsigned long address, pmd_t *pmdp,
|
|
pmd_t entry, int dirty)
|
|
{
|
|
int changed = !pmd_same(*pmdp, entry);
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
if (changed) {
|
|
set_pmd_at(vma->vm_mm, address, pmdp, entry);
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
}
|
|
return changed;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
|
|
int pmdp_clear_flush_young(struct vm_area_struct *vma,
|
|
unsigned long address, pmd_t *pmdp)
|
|
{
|
|
int young;
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
young = pmdp_test_and_clear_young(vma, address, pmdp);
|
|
if (young)
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return young;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
|
|
pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
pmd_t pmd;
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
|
|
!pmd_devmap(*pmdp));
|
|
pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return pmd;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
|
|
pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pud_t *pudp)
|
|
{
|
|
pud_t pud;
|
|
|
|
VM_BUG_ON(address & ~HPAGE_PUD_MASK);
|
|
VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
|
|
pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
|
|
flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
|
|
return pud;
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
|
|
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
|
|
pgtable_t pgtable)
|
|
{
|
|
assert_spin_locked(pmd_lockptr(mm, pmdp));
|
|
|
|
/* FIFO */
|
|
if (!pmd_huge_pte(mm, pmdp))
|
|
INIT_LIST_HEAD(&pgtable->lru);
|
|
else
|
|
list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
|
|
pmd_huge_pte(mm, pmdp) = pgtable;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
|
|
/* no "address" argument so destroys page coloring of some arch */
|
|
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
|
|
{
|
|
pgtable_t pgtable;
|
|
|
|
assert_spin_locked(pmd_lockptr(mm, pmdp));
|
|
|
|
/* FIFO */
|
|
pgtable = pmd_huge_pte(mm, pmdp);
|
|
pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
|
|
struct page, lru);
|
|
if (pmd_huge_pte(mm, pmdp))
|
|
list_del(&pgtable->lru);
|
|
return pgtable;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_INVALIDATE
|
|
pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return old;
|
|
}
|
|
#endif
|
|
|
|
#ifndef pmdp_collapse_flush
|
|
pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
/*
|
|
* pmd and hugepage pte format are same. So we could
|
|
* use the same function.
|
|
*/
|
|
pmd_t pmd;
|
|
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
VM_BUG_ON(pmd_trans_huge(*pmdp));
|
|
pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
|
|
|
|
/* collapse entails shooting down ptes not pmd */
|
|
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return pmd;
|
|
}
|
|
#endif
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
|