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

Jens Axboe
2022-05-05T19:11:18Z

On 5/5/22 1:03 PM, Jens Axboe wrote:
> 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?

This might be better, though you'd only notice if you had integrity
enabled. Christoph, I'm folding this in with patch 3...

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 8fe7ad18a709..3d827789b536 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -21,9 +21,13 @@ static void __user *nvme_to_user_ptr(uintptr_t ptrval)

static inline void *nvme_meta_from_bio(struct bio *bio)
{
- struct bio_integrity_payload *bip = bio_integrity(bio);
+ if (bio) {
+ struct bio_integrity_payload *bip = bio_integrity(bio);

- return bip ? bvec_virt(bip->bip_vec) : NULL;
+ return bip ? bvec_virt(bip->bip_vec) : NULL;
+ }
+
+ return NULL;
}

/*
@@ -205,19 +209,20 @@ 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);
+ int ret;

ret = nvme_execute_passthru_rq(req);

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