KVM: s390/mm: Fix page table locking vs. split pmd lock (55e4283c) · Commits · 戴 / test

commit (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 <borntraeger@de.ibm.com> Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/pgtable.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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;

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