Re: fix broken locking in x25 ioctl error paths
From: Dave Jones <hidden>
Date: 2013-06-28 15:36:17
On Fri, Jun 28, 2013 at 08:19:35AM -0700, Eric Dumazet wrote:
> On Fri, 2013-06-28 at 11:14 -0400, Dave Jones wrote:
> > Two of the x25 ioctl cases have error paths that break out of the function without
> > unlocking the socket, leading to this warning:
> >
> >
> > ================================================
> > [ BUG: lock held when returning to user space! ]
> > 3.10.0-rc7+ #36 Not tainted
> > ------------------------------------------------
> > trinity-child2/31407 is leaving the kernel with locks still held!
> > 1 lock held by trinity-child2/31407:
> > #0: (sk_lock-AF_X25){+.+.+.}, at: [<ffffffffa024b6da>] x25_ioctl+0x8a/0x740 [x25]
> >
> > Signed-off-by: Dave Jones [off-list ref]
> >
> > diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
> > index 37ca969..2c1e633 100644
> > --- a/net/x25/af_x25.c
> > +++ b/net/x25/af_x25.c
> > @@ -1584,10 +1584,11 @@ out_cud_release:
> > rc = -EINVAL;
> > lock_sock(sk);
> > if (sk->sk_state != TCP_CLOSE)
> > - break;
> > + goto out_callaccpt_release;
> > clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
> > - release_sock(sk);
> > rc = 0;
> > +out_callaccpt_release:
> > + release_sock(sk);
> > break;
> > }
>
> Or :
>
> lock_sock(sk);
> if (sk->sk_state == TCP_CLOSE) {
> clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
> rc = 0;
> }
> release_sock(sk);
> break;
I can do that if it's preferred. I just copied the same style
as the existing cases.
Dave