The unmap_range function did not properly cover the case when the start address was not aligned to PMD_SIZE or PUD_SIZE and an entire pte table or pmd table was cleared, causing us to leak memory when incrementing the addr.
The fix is to always move onto the next page table entry boundary instead of adding the full size of the VA range covered by the corresponding table level entry.
Acked-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org --- arch/arm/kvm/mmu.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index ca6bea4..80a83ec 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -132,37 +132,37 @@ static void unmap_range(struct kvm *kvm, pgd_t *pgdp, pmd_t *pmd; pte_t *pte; unsigned long long addr = start, end = start + size; - u64 range; + u64 next;
while (addr < end) { pgd = pgdp + pgd_index(addr); pud = pud_offset(pgd, addr); if (pud_none(*pud)) { - addr += PUD_SIZE; + addr = pud_addr_end(addr, end); continue; }
pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { - addr += PMD_SIZE; + addr = pmd_addr_end(addr, end); continue; }
pte = pte_offset_kernel(pmd, addr); clear_pte_entry(kvm, pte, addr); - range = PAGE_SIZE; + next = addr + PAGE_SIZE;
/* If we emptied the pte, walk back up the ladder */ if (pte_empty(pte)) { clear_pmd_entry(kvm, pmd, addr); - range = PMD_SIZE; + next = pmd_addr_end(addr, end); if (pmd_empty(pmd)) { clear_pud_entry(kvm, pud, addr); - range = PUD_SIZE; + next = pud_addr_end(addr, end); } }
- addr += range; + addr = next; } }