When USE_SPLIT_PTE_PTLOCKS is false, xen_pte_lock() actually do nothing
but returns NULL. So xen_pte_unlock() should not actually unlock.
Otherwise a NULL pointer dereference will be triggered.
Fixes: 74260714c56d ("xen: lock pte pages while pinning/unpinning")
Signed-off-by: Jason Yan <yanaijie@huawei.com>
---
arch/x86/xen/mmu_pv.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index eda78144c000..c70cbdf5c0fa 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -656,8 +656,10 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
static void xen_pte_unlock(void *v)
{
+#if USE_SPLIT_PTE_PTLOCKS
spinlock_t *ptl = v;
spin_unlock(ptl);
+#endif
}
static void xen_do_pin(unsigned level, unsigned long pfn)
--
2.25.4