diff --git a/drivers/gpu/nvgpu/os/posix/io.c b/drivers/gpu/nvgpu/os/posix/io.c
index 8369e73f6..0f611f029 100644
--- a/drivers/gpu/nvgpu/os/posix/io.c
+++ b/drivers/gpu/nvgpu/os/posix/io.c
@@ -253,7 +253,7 @@ struct nvgpu_posix_io_reg_space *nvgpu_posix_io_get_reg_space(struct gk20a *g,
 			nvgpu_posix_io_reg_space, link) {
 		u32 offset = addr - reg_space->base;
 
-		if ((addr >= reg_space->base) && (offset <= reg_space->size)) {
+		if ((addr >= reg_space->base) && (offset < reg_space->size)) {
 			return reg_space;
 		}
 	}
diff --git a/userspace/units/posix-mockio/posix-mockio.c b/userspace/units/posix-mockio/posix-mockio.c
index 334905bb0..032c3960b 100644
--- a/userspace/units/posix-mockio/posix-mockio.c
+++ b/userspace/units/posix-mockio/posix-mockio.c
@@ -268,7 +268,7 @@ static int test_register_space(struct unit_module *m, struct gk20a *g,
 	if (value != 0x87654321) {
 		return UNIT_FAIL;
 	}
-	nvgpu_posix_io_writel_reg_space(g, 0x10000100, 0x2727);
+	nvgpu_posix_io_writel_reg_space(g, 0x100000FC, 0x2727);
 
 	/* Now re-define the callbacks to perform our own testing */
 	struct nvgpu_posix_io_callbacks *old_cbs = nvgpu_posix_register_io(g,