Re: [PATCH v4 3/5] nvme: refactor nvme_submit_user_cmd()

Jens Axboe
2022-05-05T19:03:31Z

On 5/5/22 12:37 PM, Clay Mayers wrote:
>> From: Kanchan Joshi
>> Sent: Wednesday, May 4, 2022 11:06 PM
>> ---
>
>> drivers/nvme/host/ioctl.c | 47 ++++++++++++++++++++++++++++++++++-----
>> 1 file changed, 42 insertions(+), 5 deletions(-)
>>
>> +static int nvme_execute_user_rq(struct request *req, void __user
>> *meta_buffer,
>> + unsigned meta_len, u64 *result)
>> +{
>> + struct bio *bio = req->bio;
>> + bool write = bio_op(bio) == REQ_OP_DRV_OUT;
>
> I'm getting a NULL ptr access on the first ioctl(NVME_IOCTL_ADMIN64_CMD)
> I send - it has no ubuffer so I think there's no req->bio.

Does this work?

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 8fe7ad18a709..f615a791a7cd 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -205,7 +205,6 @@ static int nvme_execute_user_rq(struct request *req, void __user *meta_buffer,
unsigned meta_len, u64 *result)
{
struct bio *bio = req->bio;
- bool write = bio_op(bio) == REQ_OP_DRV_OUT;
int ret;
void *meta = nvme_meta_from_bio(bio);

@@ -213,11 +212,13 @@ static int nvme_execute_user_rq(struct request *req, void __user *meta_buffer,

if (result)
*result = le64_to_cpu(nvme_req(req)->result.u64);
- if (meta && !ret && !write) {
- if (copy_to_user(meta_buffer, meta, meta_len))
+ if (meta) {
+ bool write = bio_op(bio) == REQ_OP_DRV_OUT;
+
+ if (!ret && !write && copy_to_user(meta_buffer, meta, meta_len))
ret = -EFAULT;
+ kfree(meta);
}
- kfree(meta);
if (bio)
blk_rq_unmap_user(bio);
blk_mq_free_request(req);

--
Jens Axboe