On Mon, Oct 31, 2022 at 06:56 PM +01, Jakub Sitnicki wrote:
> On Sat, Oct 29, 2022 at 07:44 AM +08, Wang Yufen wrote:
>> When running `test_sockmap` selftests, got the following warning:
>>
>> WARNING: CPU: 2 PID: 197 at net/core/stream.c:205 sk_stream_kill_queues+0xd3/0xf0
>> Call Trace:
>> <TASK>
>> inet_csk_destroy_sock+0x55/0x110
>> tcp_rcv_state_process+0xd28/0x1380
>> ? tcp_v4_do_rcv+0x77/0x2c0
>> tcp_v4_do_rcv+0x77/0x2c0
>> __release_sock+0x106/0x130
>> __tcp_close+0x1a7/0x4e0
>> tcp_close+0x20/0x70
>> inet_release+0x3c/0x80
>> __sock_release+0x3a/0xb0
>> sock_close+0x14/0x20
>> __fput+0xa3/0x260
>> task_work_run+0x59/0xb0
>> exit_to_user_mode_prepare+0x1b3/0x1c0
>> syscall_exit_to_user_mode+0x19/0x50
>> do_syscall_64+0x48/0x90
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> The root case is: In commit 84472b436e76 ("bpf, sockmap: Fix more
>> uncharged while msg has more_data") , I used msg->sg.size replace
>> tosend rudely, which break the
>> if (msg->apply_bytes && msg->apply_bytes < send)
>> scene.
>>
>> Fixes: 84472b436e76 ("bpf, sockmap: Fix more uncharged while msg has more_data")
>> Reported-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
>> Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx>
>> Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
>> ---
>> v1 -> v2: typo fixup
>> net/ipv4/tcp_bpf.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
>> index a1626af..774d481 100644
>> --- a/net/ipv4/tcp_bpf.c
>> +++ b/net/ipv4/tcp_bpf.c
>> @@ -278,7 +278,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
>> {
>> bool cork = false, enospc = sk_msg_full(msg);
>> struct sock *sk_redir;
>> - u32 tosend, delta = 0;
>> + u32 tosend, orgsize, sent, delta = 0;
>> u32 eval = __SK_NONE;
>> int ret;
>>
>> @@ -333,10 +333,12 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
>> cork = true;
>> psock->cork = NULL;
>> }
>> - sk_msg_return(sk, msg, msg->sg.size);
>> + sk_msg_return(sk, msg, tosend);
>> release_sock(sk);
>>
>> + orgsize = msg->sg.size;
>> ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags);
>> + sent = orgsize - msg->sg.size;
>
> If I'm reading the code right, it's the same as:
>
> sent = tosend - msg->sg.size;
>
> If so, no need for orgsize.
Sorry, that doesn't make any sense. I misread the code.
The fix is correct.
If I can have a small ask to rename `orgsize` to something more common.
We have `orig_size` or `origsize` in use today, but no `orgsize`:
$ git grep -c '\<orig_size\>' -- net
net/core/sysctl_net_core.c:3
net/psample/psample.c:1
net/tls/tls_device.c:5
net/tls/tls_sw.c:7
$ git grep -c '\<origsize\>' -- net
net/bridge/netfilter/ebtables.c:5
net/ipv4/netfilter/arp_tables.c:10
net/ipv4/netfilter/ip_tables.c:10
net/ipv6/netfilter/ip6_tables.c:10
It reads a bit better, IMHO.
Thanks for fixing it so quickly.
Acked-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
