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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2017-04-09 22:09:38 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-04-12 07:40:24 +0200 |
| commit | a8f60d1fadf7b8b54449fcc9d6b15248917478ba (patch) | |
| tree | 6e0b4aa27aeb23303c60bdef88cff8dd80eaccb4 /arch | |
| parent | c08e611b7d0169b513e3b4515ffd51ac7f37f22c (diff) | |
| download | linux-0-day-a8f60d1fadf7b8b54449fcc9d6b15248917478ba.tar.gz linux-0-day-a8f60d1fadf7b8b54449fcc9d6b15248917478ba.tar.xz | |
s390/mm: fix CMMA vs KSM vs others
On heavy paging with KSM I see guest data corruption. Turns out that
KSM will add pages to its tree, where the mapping return true for
pte_unused (or might become as such later). KSM will unmap such pages
and reinstantiate with different attributes (e.g. write protected or
special, e.g. in replace_page or write_protect_page)). This uncovered
a bug in our pagetable handling: We must remove the unused flag as
soon as an entry becomes present again.
Cc: stable@vger.kernel.org
Signed-of-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 93e37b12e8823..ecec682bb5166 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1051,6 +1051,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, { if (!MACHINE_HAS_NX) pte_val(entry) &= ~_PAGE_NOEXEC; + if (pte_present(entry)) + pte_val(entry) &= ~_PAGE_UNUSED; if (mm_has_pgste(mm)) ptep_set_pte_at(mm, addr, ptep, entry); else |