Re: [PATCH] crypto: caam - free qman_fq after kill_fq

[Horia Geantă]

On 7/11/2017 9:21 AM, Xulin Sun wrote:
> kill_fq removes a complete frame queue, it needs to free the qman_fq
> in the last. Else kmemleak will report the below warning:
> 
> unreferenced object 0xffff800073085c80 (size 128):
>   comm "cryptomgr_test", pid 199, jiffies 4294937850 (age 67.840s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 a0 80 7e 00 00 80 ff ff
>     00 00 00 00 00 00 00 00 04 00 04 00 5c 01 00 00
>   backtrace:
>     [<ffff8000001e5760>] create_object+0xf8/0x258
>     [<ffff800000994e38>] kmemleak_alloc+0x58/0xa0
>     [<ffff8000001d5f18>] kmem_cache_alloc_trace+0x2c8/0x358
>     [<ffff8000007e8410>] create_caam_req_fq+0x40/0x170
>     [<ffff8000007e870c>] caam_drv_ctx_update+0x54/0x248
>     [<ffff8000007fca54>] aead_setkey+0x154/0x300
>     [<ffff800000452120>] setkey+0x50/0xf0
>     [<ffff80000045b144>] __test_aead+0x5ec/0x1028
>     [<ffff80000045c28c>] test_aead+0x44/0xc8
>     [<ffff80000045c368>] alg_test_aead+0x58/0xd0
>     [<ffff80000045bdb4>] alg_test+0x14c/0x308
>     [<ffff8000004588e8>] cryptomgr_test+0x50/0x58
>     [<ffff8000000c3b2c>] kthread+0xdc/0xf0
>     [<ffff800000083c00>] ret_from_fork+0x10/0x50
> 
> And check where the function kill_fq() is called to remove
> the additional kfree to qman_fq.
> 
> Signed-off-by: Xulin Sun <xulin.sun@xxxxxxxxxxxxx>
> ---
>  drivers/crypto/caam/qi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/caam/qi.c b/drivers/crypto/caam/qi.c
> index 1990ed4..c4b9173 100644
> --- a/drivers/crypto/caam/qi.c
> +++ b/drivers/crypto/caam/qi.c
> @@ -277,6 +277,7 @@ static int kill_fq(struct device *qidev, struct qman_fq *fq)
>  		dev_err(qidev, "OOS of FQID: %u failed\n", fq->fqid);
>  
>  	qman_destroy_fq(fq);
> +	kfree(fq);

There is a case where kfree(fq) is executed and kill_fq() returns != 0 -
that is when qman_oos_fq() returns != 0.

Thus please make sure there is no reference to "fq" after kill_fq(...,
fq) is called, even if kill_fq() return code is != 0.
For e.g.:
	if (kill_fq(qidev, new_fq))
		dev_warn(qidev, "New CAAM FQ: %u kill failed\n",
                         new_fq->fqid);
                         ^^^^^^ already kfree-ed

Thanks,
Horia

>  
>  	return ret;
>  }
> @@ -511,7 +512,6 @@ int caam_qi_shutdown(struct device *qidev)
>  
>  		if (kill_fq(qidev, per_cpu(pcpu_qipriv.rsp_fq, i)))
>  			dev_err(qidev, "Rsp FQ kill failed, cpu: %d\n", i);
> -		kfree(per_cpu(pcpu_qipriv.rsp_fq, i));
>  	}
>  
>  	/*
>