Re: [PATCH bpf-next] selftests/bpf: Add F_SETFL for fcntl

[John Fastabend <john.fastabend@gmail.com>]

Geliang Tang wrote:
> Hi Jakub,
>  
> On Wed, 2024-04-03 at 15:29 -0700, John Fastabend wrote:
> > Jakub Sitnicki wrote:
> > > Hi Geliang,
> > > 
> > > On Wed, Apr 03, 2024 at 04:32 PM +08, Geliang Tang wrote:
> > > > From: Geliang Tang <tanggeliang@kylinos.cn>
> > > > 
> > > > Incorrect arguments are passed to fcntl() in test_sockmap.c when
> > > > invoking
> > > > it to set file status flags. If O_NONBLOCK is used as 2nd
> > > > argument and
> > > > passed into fcntl, -EINVAL will be returned (See do_fcntl() in
> > > > fs/fcntl.c).
> > > > The correct approach is to use F_SETFL as 2nd argument, and
> > > > O_NONBLOCK as
> > > > 3rd one.
> > > > 
> > > > Fixes: 16962b2404ac ("bpf: sockmap, add selftests")
> > > > Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> > > > ---
> > > >  tools/testing/selftests/bpf/test_sockmap.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/tools/testing/selftests/bpf/test_sockmap.c
> > > > b/tools/testing/selftests/bpf/test_sockmap.c
> > > > index 024a0faafb3b..34d6a1e6f664 100644
> > > > --- a/tools/testing/selftests/bpf/test_sockmap.c
> > > > +++ b/tools/testing/selftests/bpf/test_sockmap.c
> > > > @@ -603,7 +603,7 @@ static int msg_loop(int fd, int iov_count,
> > > > int iov_length, int cnt,
> > > >  		struct timeval timeout;
> > > >  		fd_set w;
> > > >  
> > > > -		fcntl(fd, fd_flags);
> > > > +		fcntl(fd, F_SETFL, fd_flags);
> > > >  		/* Account for pop bytes noting each iteration
> > > > of apply will
> > > >  		 * call msg_pop_data helper so we need to
> > > > account for this
> > > >  		 * by calculating the number of apply
> > > > iterations. Note user
> > > 
> > > Good catch. But we also need to figure out why some tests failing
> > > with
> > > this patch applied and fix them in one go:
> > > 
> > > # 6/ 7  sockmap::txmsg test skb:FAIL
> > > #21/ 7 sockhash::txmsg test skb:FAIL
> > > #36/ 7 sockhash:ktls:txmsg test skb:FAIL
> > > Pass: 42 Fail: 3
> 
> Sorry, I didn't notice these fails in my testing before, they do exist.
> I'll try to fix them and sent a v2 soon.

Not 100% sure but a hint. I would look into where the stream parser
is waking up the sock here. I'm not sure there is an easy fix tbh.
I can help look at this soon as well if you don't beat me to a fix.

Thanks for looking into it.

> 
> Thanks,
> -Geliang