From 55e4283c3eb1d850893f645dd695c9c75d5fa1fc Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 25 Jul 2014 14:23:29 +0200 Subject: [PATCH] KVM: s390/mm: Fix page table locking vs. split pmd lock commit ec66ad66a0de87866be347b5ecc83bd46427f53b (s390/mm: enable split page table lock for PMD level) activated the split pmd lock for s390. Turns out that we missed one place: We also have to take the pmd lock instead of the page table lock when we reallocate the page tables (==> changing entries in the PMD) during sie enablement. Cc: stable@vger.kernel.org # 3.15+ Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/mm/pgtable.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 37b8241ec784..f90ad8592b36 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -1279,6 +1279,7 @@ static unsigned long page_table_realloc_pmd(struct mmu_gather *tlb, { unsigned long next, *table, *new; struct page *page; + spinlock_t *ptl; pmd_t *pmd; pmd = pmd_offset(pud, addr); @@ -1296,7 +1297,7 @@ again: if (!new) return -ENOMEM; - spin_lock(&mm->page_table_lock); + ptl = pmd_lock(mm, pmd); if (likely((unsigned long *) pmd_deref(*pmd) == table)) { /* Nuke pmd entry pointing to the "short" page table */ pmdp_flush_lazy(mm, addr, pmd); @@ -1310,7 +1311,7 @@ again: page_table_free_rcu(tlb, table); new = NULL; } - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); if (new) { page_table_free_pgste(new); goto again; -- 2.20.1