Hi Marcel,
>I finally managed to reproduce it. It does not always happen. And strangely
enough I can only trigger it when enabling experimental features of bluetoothd
with -E command line switch.
>
>But I have no idea why your bisecting points to that specific commit. And
more important it used to work just fine (see below). However I can tell you
what makes the code crash.
>
>0x1313 is in rfcomm_sock_getsockopt (net/bluetooth/rfcomm/sock.c:743).
>738
>739 static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname,
char __user *optval, int __user *optlen)
>740 {
>741 struct sock *sk = sock->sk;
>742 struct rfcomm_conninfo cinfo;
>743 struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
>744 int len, err = 0;
>745 u32 opt;
>746
>747 BT_DBG("sk %p", sk);
>
>The l2cap_pi(sk) is fully broken. That is an rfcomm_pi(sk). The commit that
broke this is actually from an earlier time. I have this one:
>
>commit 8c1d787be4b62d2d1b6f04953eca4bcf7c839d44
>Author: Gustavo F. Padovan <padovan@xxxxxxxxxxxxxx>
>Date: Wed Apr 13 20:23:55 2011 -0300
>
> Bluetooth: Move conn to struct l2cap_chan
>
>diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
>index 66cc1f0c3df8..386cfaffd4b7 100644
>--- a/net/bluetooth/rfcomm/sock.c
>+++ b/net/bluetooth/rfcomm/sock.c
>@@ -743,6 +743,7 @@ static int rfcomm_sock_getsockopt_old(struct socket
*sock, int optname, char __u
> struct sock *sk = sock->sk;
> struct sock *l2cap_sk;
> struct rfcomm_conninfo cinfo;
>+ struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
> int len, err = 0;
> u32 opt;
>
>@@ -787,8 +788,8 @@ static int rfcomm_sock_getsockopt_old(struct socket
*sock, int optname, char __u
>
> l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
>
>- cinfo.hci_handle = l2cap_pi(l2cap_sk)->conn->hcon->handle;
>- memcpy(cinfo.dev_class, l2cap_pi(l2cap_sk)->conn->hcon-
>dev_class, 3);
>+ cinfo.hci_handle = conn->hcon->handle;
>+ memcpy(cinfo.dev_class, conn->hcon->dev_class, 3);
>
>The conversion is clearly wrong since we used to have a l2cap_sk that was
pointing to the right socket.
>
>This should have blown up month ago and not just with the latest changes we
have done to the L2CAP layer. Anyhow, you can try this small change and see if
it fixes things for you.
>
>diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
>index c4d3d423f89b..0be7619c5e5e 100644
>--- a/net/bluetooth/rfcomm/sock.c
>+++ b/net/bluetooth/rfcomm/sock.c
>@@ -739,8 +739,9 @@ static int rfcomm_sock_setsockopt(struct socket *sock,
int level, int optname, c
> static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char
__user *optval, int __user *optlen)
> {
> struct sock *sk = sock->sk;
>+ struct sock *l2cap_sk;
>+ struct l2cap_conn *conn;
> struct rfcomm_conninfo cinfo;
>- struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
> int len, err = 0;
> u32 opt;
>
>@@ -783,6 +784,9 @@ static int rfcomm_sock_getsockopt_old(struct socket
*sock, int optname, char __u
> break;
> }
>
>+ l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
>+ conn = l2cap_pi(l2cap_sk)->chan->conn;
>+
> memset(&cinfo, 0, sizeof(cinfo));
> cinfo.hci_handle = conn->hcon->handle;
> memcpy(cinfo.dev_class, conn->hcon->dev_class, 3);
>
>Regards
This patch solves the issue, I don't see the crash anymore.
Thanks,
Fabio
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