Patchwork fix broken locking in x25 ioctl error paths

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Submitter Dave Jones
Date June 28, 2013, 3:14 p.m.
Message ID <20130628151453.GA29428@redhat.com>
Download mbox | patch
Permalink /patch/255420/
State Superseded
Delegated to: David Miller
Headers show

Comments

Dave Jones - June 28, 2013, 3:14 p.m.
Two of the x25 ioctl cases have error paths that break out of the function without
unlocking the socket, leading to this warning:


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Eric Dumazet - June 28, 2013, 3:19 p.m.
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 <davej@redhat.com>
> 
> 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;


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Dave Jones - June 28, 2013, 3:36 p.m.
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 <davej@redhat.com>
 > > 
 > > 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



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Patch

================================================
[ 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 <davej@redhat.com>

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;
 	}
 
@@ -1595,14 +1596,15 @@  out_cud_release:
 		rc = -EINVAL;
 		lock_sock(sk);
 		if (sk->sk_state != TCP_ESTABLISHED)
-			break;
+			goto out_sendcallaccpt_release;
 		/* must call accptapprv above */
 		if (test_bit(X25_ACCPT_APPRV_FLAG, &x25->flags))
-			break;
+			goto out_sendcallaccpt_release;
 		x25_write_internal(sk, X25_CALL_ACCEPTED);
 		x25->state = X25_STATE_3;
-		release_sock(sk);
 		rc = 0;
+out_sendcallaccpt_release:
+		release_sock(sk);
 		break;
 	}