netdev - Re: [PATCH net 2/4] virtio/vsock: Fix sk_error

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Message-ID: <a3c80efc-94b2-463a-ab2e-e7f87245fd09@rbox.co>
Date: Thu, 7 Nov 2024 21:49:56 +0100
From: Michal Luczaj <mhal@...x.co>
To: Stefano Garzarella <sgarzare@...hat.com>
Cc: Stefan Hajnoczi <stefanha@...hat.com>, "Michael S. Tsirkin"
 <mst@...hat.com>, Jason Wang <jasowang@...hat.com>,
 Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, Eugenio Pérez
 <eperezma@...hat.com>, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>,
 Jia He <justin.he@....com>, Arseniy Krasnov <avkrasnov@...utedevices.com>,
 Dmitry Torokhov <dtor@...are.com>, Andy King <acking@...are.com>,
 George Zhang <georgezhang@...are.com>, kvm@...r.kernel.org,
 virtualization@...ts.linux.dev, netdev@...r.kernel.org
Subject: Re: [PATCH net 2/4] virtio/vsock: Fix sk_error_queue memory leak

On 11/7/24 11:17, Stefano Garzarella wrote:
> On Wed, Nov 06, 2024 at 06:51:19PM +0100, Michal Luczaj wrote:
>> Kernel queues MSG_ZEROCOPY completion notifications on the error queue.
>> Where they remain, until explicitly recv()ed. To prevent memory leaks,
>> clean up the queue when the socket is destroyed.
>>
>> unreferenced object 0xffff8881028beb00 (size 224):
>>  comm "vsock_test", pid 1218, jiffies 4294694897
>>  hex dump (first 32 bytes):
>>    90 b0 21 17 81 88 ff ff 90 b0 21 17 81 88 ff ff  ..!.......!.....
>>    00 00 00 00 00 00 00 00 00 b0 21 17 81 88 ff ff  ..........!.....
>>  backtrace (crc 6c7031ca):
>>    [<ffffffff81418ef7>] kmem_cache_alloc_node_noprof+0x2f7/0x370
>>    [<ffffffff81d35882>] __alloc_skb+0x132/0x180
>>    [<ffffffff81d2d32b>] sock_omalloc+0x4b/0x80
>>    [<ffffffff81d3a8ae>] msg_zerocopy_realloc+0x9e/0x240
>>    [<ffffffff81fe5cb2>] virtio_transport_send_pkt_info+0x412/0x4c0
>>    [<ffffffff81fe6183>] virtio_transport_stream_enqueue+0x43/0x50
>>    [<ffffffff81fe0813>] vsock_connectible_sendmsg+0x373/0x450
>>    [<ffffffff81d233d5>] ____sys_sendmsg+0x365/0x3a0
>>    [<ffffffff81d246f4>] ___sys_sendmsg+0x84/0xd0
>>    [<ffffffff81d26f47>] __sys_sendmsg+0x47/0x80
>>    [<ffffffff820d3df3>] do_syscall_64+0x93/0x180
>>    [<ffffffff8220012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>
>> Fixes: 581512a6dc93 ("vsock/virtio: MSG_ZEROCOPY flag support")
>> Signed-off-by: Michal Luczaj <mhal@...x.co>
>> ---
>> net/vmw_vsock/af_vsock.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> index 35681adedd9aaec3565495158f5342b8aa76c9bc..dfd29160fe11c4675f872c1ee123d65b2da0dae6 100644
>> --- a/net/vmw_vsock/af_vsock.c
>> +++ b/net/vmw_vsock/af_vsock.c
>> @@ -836,6 +836,9 @@ static void vsock_sk_destruct(struct sock *sk)
>> {
>> 	struct vsock_sock *vsk = vsock_sk(sk);
>>
>> +	/* Flush MSG_ZEROCOPY leftovers. */
>> +	__skb_queue_purge(&sk->sk_error_queue);
>> +
> 
> It is true that for now this is supported only in the virtio transport, 
> but it's more related to the core, so please remove `virtio` from the 
> commit title.
> 
> The rest LGTM.
> ...

OK, done. Here's v2 of the series:
https://lore.kernel.org/netdev/20241107-vsock-mem-leaks-v2-0-4e21bfcfc818@rbox.co/

Thanks for the reviews,
Michal