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mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd() 

With some architectures like ppc64, set_pmd_at() cannot cope with a
situation where there is already some (different) valid entry present.

Use pmdp_set_access_flags() instead to modify the pfn which is built to
deal with modifying existing PMD entries.

This is similar to commit cae85cb8ad ("mm/memory.c: fix modifying of
page protection by insert_pfn()")

We also do similar update w.r.t insert_pfn_pud eventhough ppc64 don't
support pud pfn entries now.

Without this patch we also see the below message in kernel log "BUG:
non-zero pgtables_bytes on freeing mm:"

Link: http://lkml.kernel.org/r/20190402115125.18803-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Chandan Rajendra <chandan@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Aneesh Kumar K.V 2019-04-05 18:39:10 -07:00 committed by Linus Torvalds
parent 58b6e5e8f1
commit c6f3c5ee40
1 changed files with 36 additions and 0 deletions
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36
mm/huge_memory.c
View File

@ -755,6 +755,21 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
spinlock_t *ptl;
ptl = pmd_lock(mm, pmd);
if (!pmd_none(*pmd)) {
if (write) {
if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) {
WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
goto out_unlock;
}
entry = pmd_mkyoung(*pmd);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
update_mmu_cache_pmd(vma, addr, pmd);
}
goto out_unlock;
}
entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
if (pfn_t_devmap(pfn))
entry = pmd_mkdevmap(entry);
@ -766,11 +781,16 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
if (pgtable) {
pgtable_trans_huge_deposit(mm, pmd, pgtable);
mm_inc_nr_ptes(mm);
pgtable = NULL;
}
set_pmd_at(mm, addr, pmd, entry);
update_mmu_cache_pmd(vma, addr, pmd);
out_unlock:
spin_unlock(ptl);
if (pgtable)
pte_free(mm, pgtable);
}
vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@ -821,6 +841,20 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
spinlock_t *ptl;
ptl = pud_lock(mm, pud);
if (!pud_none(*pud)) {
if (write) {
if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
WARN_ON_ONCE(!is_huge_zero_pud(*pud));
goto out_unlock;
}
entry = pud_mkyoung(*pud);
entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
if (pudp_set_access_flags(vma, addr, pud, entry, 1))
update_mmu_cache_pud(vma, addr, pud);
}
goto out_unlock;
}
entry = pud_mkhuge(pfn_t_pud(pfn, prot));
if (pfn_t_devmap(pfn))
entry = pud_mkdevmap(entry);
@ -830,6 +864,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
}
set_pud_at(mm, addr, pud, entry);
update_mmu_cache_pud(vma, addr, pud);
out_unlock:
spin_unlock(ptl);
}