Re: [PATCH] RDMA/hfi1: fix potential memory leak in setup_base_ctxt()

From: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Jianglei Nie <niejianglei2021@163.com>,
	jgg@ziepe.ca, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/hfi1: fix potential memory leak in setup_base_ctxt()
Date: Mon, 18 Jul 2022 08:11:59 -0400	[thread overview]
Message-ID: <be437471-0080-8e9c-978a-6029c7826335@cornelisnetworks.com> (raw)
In-Reply-To: <YtU4eXQCVEPGnh9b@unreal>

On 7/18/22 6:39 AM, Leon Romanovsky wrote:
> On Mon, Jul 11, 2022 at 07:52:25AM -0400, Dennis Dalessandro wrote:
>> On 7/11/22 3:07 AM, Jianglei Nie wrote:
>>> setup_base_ctxt() allocates a memory chunk for uctxt->groups with
>>> hfi1_alloc_ctxt_rcv_groups(). When init_user_ctxt() fails, uctxt->groups
>>> is not released, which will lead to a memory leak.
>>>
>>> We should release the uctxt->groups with hfi1_free_ctxt_rcv_groups()
>>> when init_user_ctxt() fails.
>>>
>>> Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
>>> ---
>>>  drivers/infiniband/hw/hfi1/file_ops.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
>>> index 2e4cf2b11653..629beff053ad 100644
>>> --- a/drivers/infiniband/hw/hfi1/file_ops.c
>>> +++ b/drivers/infiniband/hw/hfi1/file_ops.c
>>> @@ -1179,8 +1179,10 @@ static int setup_base_ctxt(struct hfi1_filedata *fd,
>>>  		goto done;
>>>  
>>>  	ret = init_user_ctxt(fd, uctxt);
>>> -	if (ret)
>>> +	if (ret) {
>>> +		hfi1_free_ctxt_rcv_groups(uctxt);
>>>  		goto done;
>>> +	}
>>>  
>>>  	user_init(uctxt);
>>>  
>>
>> Doesn't seem like this patch is correct. The free is done when the file is
>> closed, along with other clean up stuff. See hfi1_file_close().
> 
> Can setup_base_ctxt() be called twice for same uctxt?
> You are allocating rcd->groups and not releasing.

The first thing assign_ctxt() does is a check of the fd->uctxt and it bails with
-EINVAL. So effectively only once.

-Denny