fs: NFSv4.1: Fix memory leakage

[PATCH] fs: NFSv4.1: Fix memory leakage

Posted by Konstantin Meskhidze 2 years, 9 months ago

This commit fixes potential memory leakage of 'calldata' memory chunk
in _nfs41_proc_sequence() function.

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
---
 fs/nfs/nfs4proc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 86ed5c0142c3..b7aa66167341 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9416,8 +9416,10 @@ static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
 	task_setup_data.callback_data = calldata;
 
 	ret = rpc_run_task(&task_setup_data);
-	if (IS_ERR(ret))
+	if (IS_ERR(ret)) {
+		kfree(calldata);
 		goto out_err;
+	}
 	return ret;
 out_put_clp:
 	nfs_put_client(clp);
-- 
2.25.1

Re: [PATCH] NFSv4.1: Fix memory leakage

Posted by Benjamin Coddington 2 years, 9 months ago

On 8 Dec 2022, at 21:18, Konstantin Meskhidze wrote:

> This commit fixes potential memory leakage of 'calldata' memory chunk
> in _nfs41_proc_sequence() function.
>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
> ---
>  fs/nfs/nfs4proc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 86ed5c0142c3..b7aa66167341 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -9416,8 +9416,10 @@ static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
>  	task_setup_data.callback_data = calldata;
>
>  	ret = rpc_run_task(&task_setup_data);
> -	if (IS_ERR(ret))
> +	if (IS_ERR(ret)) {
> +		kfree(calldata);
>  		goto out_err;
> +	}
>  	return ret;
>  out_put_clp:
>  	nfs_put_client(clp);
> -- 
> 2.25.1

Did you observe this leak, or find it by code inspecton?

I don't think there's a leak here because there's no way rpc_run_task() can
return an error withouth also doing rpc_call_ops->rpc_release, which should
free the calldata.

Ben

Re: [PATCH] NFSv4.1: Fix memory leakage

Posted by Trond Myklebust 2 years, 9 months ago


> On Dec 9, 2022, at 07:29, Benjamin Coddington <bcodding@redhat.com> wrote:
> 
> On 8 Dec 2022, at 21:18, Konstantin Meskhidze wrote:
> 
>> This commit fixes potential memory leakage of 'calldata' memory chunk
>> in _nfs41_proc_sequence() function.
>> 
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
>> ---
>> fs/nfs/nfs4proc.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index 86ed5c0142c3..b7aa66167341 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -9416,8 +9416,10 @@ static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
>> task_setup_data.callback_data = calldata;
>> 
>> ret = rpc_run_task(&task_setup_data);
>> - if (IS_ERR(ret))
>> + if (IS_ERR(ret)) {
>> + kfree(calldata);
>> goto out_err;
>> + }
>> return ret;
>> out_put_clp:
>> nfs_put_client(clp);
>> -- 
>> 2.25.1
> 
> Did you observe this leak, or find it by code inspecton?
> 
> I don't think there's a leak here because there's no way rpc_run_task() can
> return an error withouth also doing rpc_call_ops->rpc_release, which should
> free the calldata.

Correct. We will not be applying this patch.
_________________________________
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com