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* [PATCH v2] Bluetooth: fix inconsistent lock state in sco
@ 2021-07-13 16:28 Desmond Cheong Zhi Xi
  2021-07-14 19:12 ` Luiz Augusto von Dentz
  0 siblings, 1 reply; 3+ messages in thread
From: Desmond Cheong Zhi Xi @ 2021-07-13 16:28 UTC (permalink / raw)
  To: marcel, johan.hedberg, luiz.dentz, davem, kuba, stefan
  Cc: Desmond Cheong Zhi Xi, linux-bluetooth, netdev, linux-kernel,
	skhan, gregkh, linux-kernel-mentees, syzbot+2f6d7c28bb4bf7e82060

Syzbot reported an inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} lock
usage in sco_conn_del and sco_sock_timeout that could lead to
deadlocks.

This inconsistent lock state can also happen in sco_conn_ready,
rfcomm_connect_ind, and bt_accept_enqueue.

The issue is that these functions take a spin lock on the socket with
interrupts enabled, but sco_sock_timeout takes the lock in an IRQ
context. This could lead to deadlocks:

       CPU0
       ----
  lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
  <Interrupt>
    lock(slock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

We fix this by ensuring that local bh is disabled before calling
bh_lock_sock.

After doing this, we additionally need to protect sco_conn_lock by
disabling local bh.

This is necessary because sco_conn_del makes a call to sco_chan_del
while holding on to the sock lock, and sco_chan_del itself makes a
call to sco_conn_lock. If sco_conn_lock is held elsewhere with
interrupts enabled, there could still be a
slock-AF_BLUETOOTH-BTPROTO_SCO --> &conn->lock#2 lock inversion as
follows:

        CPU0                    CPU1
        ----                    ----
   lock(&conn->lock#2);
                                local_irq_disable();
                                lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
                                lock(&conn->lock#2);
   <Interrupt>
     lock(slock-AF_BLUETOOTH-BTPROTO_SCO);

  *** DEADLOCK ***

As sco_conn_del now disables local bh before calling sco_chan_del,
instead of disabling local bh for the calls to sco_conn_lock in
sco_chan_del, we instead wrap other calls to sco_chan_del with
local_bh_disable/enable.

Reported-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
Tested-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
---

Hi,

The previous version of this patch was a bit of a mess, so I made the
following changes.

v1 -> v2:
- Instead of pulling out the clean-up code out from sco_chan_del and
using it directly in sco_conn_del, disable local irqs for relevant
sections.
- Disable local irqs more thoroughly for instances of
bh_lock_sock/bh_lock_sock_nested in the bluetooth subsystem.
Specifically, the calls in af_bluetooth.c and rfcomm/sock.c are now made
with local irqs disabled as well.

Best wishes,
Desmond

 net/bluetooth/rfcomm/sock.c |  2 ++
 net/bluetooth/sco.c         | 26 +++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index ae6f80730561..d8734abb2df4 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -974,6 +974,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
 	if (!parent)
 		return 0;
 
+	local_bh_disable();
 	bh_lock_sock(parent);
 
 	/* Check for backlog size */
@@ -1002,6 +1003,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
 
 done:
 	bh_unlock_sock(parent);
+	local_bh_enable();
 
 	if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
 		parent->sk_state_change(parent);
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 3bd41563f118..2548b8f81473 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -167,16 +167,22 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
 	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
 
 	/* Kill socket */
+	local_bh_disable();
 	sco_conn_lock(conn);
 	sk = conn->sk;
 	sco_conn_unlock(conn);
+	local_bh_enable();
 
 	if (sk) {
 		sock_hold(sk);
+
+		local_bh_disable();
 		bh_lock_sock(sk);
 		sco_sock_clear_timer(sk);
 		sco_chan_del(sk, err);
 		bh_unlock_sock(sk);
+		local_bh_enable();
+
 		sco_sock_kill(sk);
 		sock_put(sk);
 	}
@@ -202,6 +208,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
 {
 	int err = 0;
 
+	local_bh_disable();
 	sco_conn_lock(conn);
 	if (conn->sk)
 		err = -EBUSY;
@@ -209,6 +216,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
 		__sco_chan_add(conn, sk, parent);
 
 	sco_conn_unlock(conn);
+	local_bh_enable();
 	return err;
 }
 
@@ -303,9 +311,11 @@ static void sco_recv_frame(struct sco_conn *conn, struct sk_buff *skb)
 {
 	struct sock *sk;
 
+	local_bh_disable();
 	sco_conn_lock(conn);
 	sk = conn->sk;
 	sco_conn_unlock(conn);
+	local_bh_enable();
 
 	if (!sk)
 		goto drop;
@@ -420,18 +430,25 @@ static void __sco_sock_close(struct sock *sk)
 		if (sco_pi(sk)->conn->hcon) {
 			sk->sk_state = BT_DISCONN;
 			sco_sock_set_timer(sk, SCO_DISCONN_TIMEOUT);
+			local_bh_disable();
 			sco_conn_lock(sco_pi(sk)->conn);
 			hci_conn_drop(sco_pi(sk)->conn->hcon);
 			sco_pi(sk)->conn->hcon = NULL;
 			sco_conn_unlock(sco_pi(sk)->conn);
-		} else
+			local_bh_enable();
+		} else {
+			local_bh_disable();
 			sco_chan_del(sk, ECONNRESET);
+			local_bh_enable();
+		}
 		break;
 
 	case BT_CONNECT2:
 	case BT_CONNECT:
 	case BT_DISCONN:
+		local_bh_disable();
 		sco_chan_del(sk, ECONNRESET);
+		local_bh_enable();
 		break;
 
 	default:
@@ -1084,21 +1101,26 @@ static void sco_conn_ready(struct sco_conn *conn)
 
 	if (sk) {
 		sco_sock_clear_timer(sk);
+		local_bh_disable();
 		bh_lock_sock(sk);
 		sk->sk_state = BT_CONNECTED;
 		sk->sk_state_change(sk);
 		bh_unlock_sock(sk);
+		local_bh_enable();
 	} else {
+		local_bh_disable();
 		sco_conn_lock(conn);
 
 		if (!conn->hcon) {
 			sco_conn_unlock(conn);
+			local_bh_enable();
 			return;
 		}
 
 		parent = sco_get_sock_listen(&conn->hcon->src);
 		if (!parent) {
 			sco_conn_unlock(conn);
+			local_bh_enable();
 			return;
 		}
 
@@ -1109,6 +1131,7 @@ static void sco_conn_ready(struct sco_conn *conn)
 		if (!sk) {
 			bh_unlock_sock(parent);
 			sco_conn_unlock(conn);
+			local_bh_enable();
 			return;
 		}
 
@@ -1131,6 +1154,7 @@ static void sco_conn_ready(struct sco_conn *conn)
 		bh_unlock_sock(parent);
 
 		sco_conn_unlock(conn);
+		local_bh_enable();
 	}
 }
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] Bluetooth: fix inconsistent lock state in sco
  2021-07-13 16:28 [PATCH v2] Bluetooth: fix inconsistent lock state in sco Desmond Cheong Zhi Xi
@ 2021-07-14 19:12 ` Luiz Augusto von Dentz
  2021-07-15  2:21   ` Desmond Cheong Zhi Xi
  0 siblings, 1 reply; 3+ messages in thread
From: Luiz Augusto von Dentz @ 2021-07-14 19:12 UTC (permalink / raw)
  To: Desmond Cheong Zhi Xi
  Cc: Marcel Holtmann, Johan Hedberg, David Miller, Jakub Kicinski,
	stefan, linux-bluetooth, open list:NETWORKING [GENERAL],
	Linux Kernel Mailing List, skhan, Greg Kroah-Hartman,
	linux-kernel-mentees, syzbot+2f6d7c28bb4bf7e82060

Hi Desmond,

On Tue, Jul 13, 2021 at 9:29 AM Desmond Cheong Zhi Xi
<desmondcheongzx@gmail.com> wrote:
>
> Syzbot reported an inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} lock
> usage in sco_conn_del and sco_sock_timeout that could lead to
> deadlocks.
>
> This inconsistent lock state can also happen in sco_conn_ready,
> rfcomm_connect_ind, and bt_accept_enqueue.
>
> The issue is that these functions take a spin lock on the socket with
> interrupts enabled, but sco_sock_timeout takes the lock in an IRQ
> context. This could lead to deadlocks:
>
>        CPU0
>        ----
>   lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>   <Interrupt>
>     lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>
>  *** DEADLOCK ***
>
> We fix this by ensuring that local bh is disabled before calling
> bh_lock_sock.
>
> After doing this, we additionally need to protect sco_conn_lock by
> disabling local bh.
>
> This is necessary because sco_conn_del makes a call to sco_chan_del
> while holding on to the sock lock, and sco_chan_del itself makes a
> call to sco_conn_lock. If sco_conn_lock is held elsewhere with
> interrupts enabled, there could still be a
> slock-AF_BLUETOOTH-BTPROTO_SCO --> &conn->lock#2 lock inversion as
> follows:
>
>         CPU0                    CPU1
>         ----                    ----
>    lock(&conn->lock#2);
>                                 local_irq_disable();
>                                 lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>                                 lock(&conn->lock#2);
>    <Interrupt>
>      lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>
>   *** DEADLOCK ***
>
> As sco_conn_del now disables local bh before calling sco_chan_del,
> instead of disabling local bh for the calls to sco_conn_lock in
> sco_chan_del, we instead wrap other calls to sco_chan_del with
> local_bh_disable/enable.
>
> Reported-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
> Tested-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
> ---
>
> Hi,
>
> The previous version of this patch was a bit of a mess, so I made the
> following changes.
>
> v1 -> v2:
> - Instead of pulling out the clean-up code out from sco_chan_del and
> using it directly in sco_conn_del, disable local irqs for relevant
> sections.
> - Disable local irqs more thoroughly for instances of
> bh_lock_sock/bh_lock_sock_nested in the bluetooth subsystem.
> Specifically, the calls in af_bluetooth.c and rfcomm/sock.c are now made
> with local irqs disabled as well.
>
> Best wishes,
> Desmond
>
>  net/bluetooth/rfcomm/sock.c |  2 ++
>  net/bluetooth/sco.c         | 26 +++++++++++++++++++++++++-
>  2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
> index ae6f80730561..d8734abb2df4 100644
> --- a/net/bluetooth/rfcomm/sock.c
> +++ b/net/bluetooth/rfcomm/sock.c
> @@ -974,6 +974,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
>         if (!parent)
>                 return 0;
>
> +       local_bh_disable();
>         bh_lock_sock(parent);
>
>         /* Check for backlog size */
> @@ -1002,6 +1003,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
>
>  done:
>         bh_unlock_sock(parent);
> +       local_bh_enable();

Looks like you are touching RFCOMM as well, perhaps you should have it
split, also how about other sockets like L2CAP and HCI are they
affected? There seems to be a lot of problem with the likes of
bh_lock_sock I wonder if going with local_bh_disable is overall a
better way to handle.

>         if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
>                 parent->sk_state_change(parent);
> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
> index 3bd41563f118..2548b8f81473 100644
> --- a/net/bluetooth/sco.c
> +++ b/net/bluetooth/sco.c
> @@ -167,16 +167,22 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
>         BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
>
>         /* Kill socket */
> +       local_bh_disable();
>         sco_conn_lock(conn);
>         sk = conn->sk;
>         sco_conn_unlock(conn);
> +       local_bh_enable();
>
>         if (sk) {
>                 sock_hold(sk);
> +
> +               local_bh_disable();
>                 bh_lock_sock(sk);
>                 sco_sock_clear_timer(sk);
>                 sco_chan_del(sk, err);
>                 bh_unlock_sock(sk);
> +               local_bh_enable();
> +
>                 sco_sock_kill(sk);
>                 sock_put(sk);
>         }
> @@ -202,6 +208,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
>  {
>         int err = 0;
>
> +       local_bh_disable();
>         sco_conn_lock(conn);
>         if (conn->sk)
>                 err = -EBUSY;
> @@ -209,6 +216,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
>                 __sco_chan_add(conn, sk, parent);
>
>         sco_conn_unlock(conn);
> +       local_bh_enable();
>         return err;
>  }
>
> @@ -303,9 +311,11 @@ static void sco_recv_frame(struct sco_conn *conn, struct sk_buff *skb)
>  {
>         struct sock *sk;
>
> +       local_bh_disable();
>         sco_conn_lock(conn);
>         sk = conn->sk;
>         sco_conn_unlock(conn);
> +       local_bh_enable();
>
>         if (!sk)
>                 goto drop;
> @@ -420,18 +430,25 @@ static void __sco_sock_close(struct sock *sk)
>                 if (sco_pi(sk)->conn->hcon) {
>                         sk->sk_state = BT_DISCONN;
>                         sco_sock_set_timer(sk, SCO_DISCONN_TIMEOUT);
> +                       local_bh_disable();
>                         sco_conn_lock(sco_pi(sk)->conn);
>                         hci_conn_drop(sco_pi(sk)->conn->hcon);
>                         sco_pi(sk)->conn->hcon = NULL;
>                         sco_conn_unlock(sco_pi(sk)->conn);
> -               } else
> +                       local_bh_enable();
> +               } else {
> +                       local_bh_disable();
>                         sco_chan_del(sk, ECONNRESET);
> +                       local_bh_enable();
> +               }
>                 break;
>
>         case BT_CONNECT2:
>         case BT_CONNECT:
>         case BT_DISCONN:
> +               local_bh_disable();
>                 sco_chan_del(sk, ECONNRESET);
> +               local_bh_enable();
>                 break;
>
>         default:
> @@ -1084,21 +1101,26 @@ static void sco_conn_ready(struct sco_conn *conn)
>
>         if (sk) {
>                 sco_sock_clear_timer(sk);
> +               local_bh_disable();
>                 bh_lock_sock(sk);
>                 sk->sk_state = BT_CONNECTED;
>                 sk->sk_state_change(sk);
>                 bh_unlock_sock(sk);
> +               local_bh_enable();
>         } else {
> +               local_bh_disable();
>                 sco_conn_lock(conn);
>
>                 if (!conn->hcon) {
>                         sco_conn_unlock(conn);
> +                       local_bh_enable();
>                         return;
>                 }
>
>                 parent = sco_get_sock_listen(&conn->hcon->src);
>                 if (!parent) {
>                         sco_conn_unlock(conn);
> +                       local_bh_enable();
>                         return;
>                 }
>
> @@ -1109,6 +1131,7 @@ static void sco_conn_ready(struct sco_conn *conn)
>                 if (!sk) {
>                         bh_unlock_sock(parent);
>                         sco_conn_unlock(conn);
> +                       local_bh_enable();
>                         return;
>                 }
>
> @@ -1131,6 +1154,7 @@ static void sco_conn_ready(struct sco_conn *conn)
>                 bh_unlock_sock(parent);
>
>                 sco_conn_unlock(conn);
> +               local_bh_enable();
>         }
>  }
>
> --
> 2.25.1
>


-- 
Luiz Augusto von Dentz

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] Bluetooth: fix inconsistent lock state in sco
  2021-07-14 19:12 ` Luiz Augusto von Dentz
@ 2021-07-15  2:21   ` Desmond Cheong Zhi Xi
  0 siblings, 0 replies; 3+ messages in thread
From: Desmond Cheong Zhi Xi @ 2021-07-15  2:21 UTC (permalink / raw)
  To: Luiz Augusto von Dentz
  Cc: Marcel Holtmann, Johan Hedberg, David Miller, Jakub Kicinski,
	stefan, linux-bluetooth, open list:NETWORKING [GENERAL],
	Linux Kernel Mailing List, skhan, Greg Kroah-Hartman,
	linux-kernel-mentees, syzbot+2f6d7c28bb4bf7e82060

On 15/7/21 3:12 am, Luiz Augusto von Dentz wrote:
> Hi Desmond,
> 
> On Tue, Jul 13, 2021 at 9:29 AM Desmond Cheong Zhi Xi
> <desmondcheongzx@gmail.com> wrote:
>>
>> Syzbot reported an inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} lock
>> usage in sco_conn_del and sco_sock_timeout that could lead to
>> deadlocks.
>>
>> This inconsistent lock state can also happen in sco_conn_ready,
>> rfcomm_connect_ind, and bt_accept_enqueue.
>>
>> The issue is that these functions take a spin lock on the socket with
>> interrupts enabled, but sco_sock_timeout takes the lock in an IRQ
>> context. This could lead to deadlocks:
>>
>>         CPU0
>>         ----
>>    lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>>    <Interrupt>
>>      lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>>
>>   *** DEADLOCK ***
>>
>> We fix this by ensuring that local bh is disabled before calling
>> bh_lock_sock.
>>
>> After doing this, we additionally need to protect sco_conn_lock by
>> disabling local bh.
>>
>> This is necessary because sco_conn_del makes a call to sco_chan_del
>> while holding on to the sock lock, and sco_chan_del itself makes a
>> call to sco_conn_lock. If sco_conn_lock is held elsewhere with
>> interrupts enabled, there could still be a
>> slock-AF_BLUETOOTH-BTPROTO_SCO --> &conn->lock#2 lock inversion as
>> follows:
>>
>>          CPU0                    CPU1
>>          ----                    ----
>>     lock(&conn->lock#2);
>>                                  local_irq_disable();
>>                                  lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>>                                  lock(&conn->lock#2);
>>     <Interrupt>
>>       lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
>>
>>    *** DEADLOCK ***
>>
>> As sco_conn_del now disables local bh before calling sco_chan_del,
>> instead of disabling local bh for the calls to sco_conn_lock in
>> sco_chan_del, we instead wrap other calls to sco_chan_del with
>> local_bh_disable/enable.
>>
>> Reported-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
>> Tested-by: syzbot+2f6d7c28bb4bf7e82060@syzkaller.appspotmail.com
>> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
>> ---
>>
>> Hi,
>>
>> The previous version of this patch was a bit of a mess, so I made the
>> following changes.
>>
>> v1 -> v2:
>> - Instead of pulling out the clean-up code out from sco_chan_del and
>> using it directly in sco_conn_del, disable local irqs for relevant
>> sections.
>> - Disable local irqs more thoroughly for instances of
>> bh_lock_sock/bh_lock_sock_nested in the bluetooth subsystem.
>> Specifically, the calls in af_bluetooth.c and rfcomm/sock.c are now made
>> with local irqs disabled as well.
>>
>> Best wishes,
>> Desmond
>>
>>   net/bluetooth/rfcomm/sock.c |  2 ++
>>   net/bluetooth/sco.c         | 26 +++++++++++++++++++++++++-
>>   2 files changed, 27 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
>> index ae6f80730561..d8734abb2df4 100644
>> --- a/net/bluetooth/rfcomm/sock.c
>> +++ b/net/bluetooth/rfcomm/sock.c
>> @@ -974,6 +974,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
>>          if (!parent)
>>                  return 0;
>>
>> +       local_bh_disable();
>>          bh_lock_sock(parent);
>>
>>          /* Check for backlog size */
>> @@ -1002,6 +1003,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
>>
>>   done:
>>          bh_unlock_sock(parent);
>> +       local_bh_enable();
> 
> Looks like you are touching RFCOMM as well, perhaps you should have it
> split, also how about other sockets like L2CAP and HCI are they
> affected? There seems to be a lot of problem with the likes of
> bh_lock_sock I wonder if going with local_bh_disable is overall a
> better way to handle.
> 

Thanks for the feedback, Luiz. I'll separate the SCO and RFCOMM code 
changes.

I believe other sockets should be fine. From what I see, they use 
lock_sock, which acquires the spin lock via spin_lock_bh under the hood. 
So only code that uses bh_lock_sock/bh_lock_sock_nested are affected.

Also I'm not sure what you meant by going with local_bh_disable? I'm 
probably missing context about Bluetooth protocols, but I think the spin 
locks still have their place to protect concurrent accesses and to make 
it clear about what's being protected.

>>          if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
>>                  parent->sk_state_change(parent);
>> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
>> index 3bd41563f118..2548b8f81473 100644
>> --- a/net/bluetooth/sco.c
>> +++ b/net/bluetooth/sco.c
>> @@ -167,16 +167,22 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
>>          BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
>>
>>          /* Kill socket */
>> +       local_bh_disable();
>>          sco_conn_lock(conn);
>>          sk = conn->sk;
>>          sco_conn_unlock(conn);
>> +       local_bh_enable();
>>
>>          if (sk) {
>>                  sock_hold(sk);
>> +
>> +               local_bh_disable();
>>                  bh_lock_sock(sk);
>>                  sco_sock_clear_timer(sk);
>>                  sco_chan_del(sk, err);
>>                  bh_unlock_sock(sk);
>> +               local_bh_enable();
>> +
>>                  sco_sock_kill(sk);
>>                  sock_put(sk);
>>          }
>> @@ -202,6 +208,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
>>   {
>>          int err = 0;
>>
>> +       local_bh_disable();
>>          sco_conn_lock(conn);
>>          if (conn->sk)
>>                  err = -EBUSY;
>> @@ -209,6 +216,7 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
>>                  __sco_chan_add(conn, sk, parent);
>>
>>          sco_conn_unlock(conn);
>> +       local_bh_enable();
>>          return err;
>>   }
>>
>> @@ -303,9 +311,11 @@ static void sco_recv_frame(struct sco_conn *conn, struct sk_buff *skb)
>>   {
>>          struct sock *sk;
>>
>> +       local_bh_disable();
>>          sco_conn_lock(conn);
>>          sk = conn->sk;
>>          sco_conn_unlock(conn);
>> +       local_bh_enable();
>>
>>          if (!sk)
>>                  goto drop;
>> @@ -420,18 +430,25 @@ static void __sco_sock_close(struct sock *sk)
>>                  if (sco_pi(sk)->conn->hcon) {
>>                          sk->sk_state = BT_DISCONN;
>>                          sco_sock_set_timer(sk, SCO_DISCONN_TIMEOUT);
>> +                       local_bh_disable();
>>                          sco_conn_lock(sco_pi(sk)->conn);
>>                          hci_conn_drop(sco_pi(sk)->conn->hcon);
>>                          sco_pi(sk)->conn->hcon = NULL;
>>                          sco_conn_unlock(sco_pi(sk)->conn);
>> -               } else
>> +                       local_bh_enable();
>> +               } else {
>> +                       local_bh_disable();
>>                          sco_chan_del(sk, ECONNRESET);
>> +                       local_bh_enable();
>> +               }
>>                  break;
>>
>>          case BT_CONNECT2:
>>          case BT_CONNECT:
>>          case BT_DISCONN:
>> +               local_bh_disable();
>>                  sco_chan_del(sk, ECONNRESET);
>> +               local_bh_enable();
>>                  break;
>>
>>          default:
>> @@ -1084,21 +1101,26 @@ static void sco_conn_ready(struct sco_conn *conn)
>>
>>          if (sk) {
>>                  sco_sock_clear_timer(sk);
>> +               local_bh_disable();
>>                  bh_lock_sock(sk);
>>                  sk->sk_state = BT_CONNECTED;
>>                  sk->sk_state_change(sk);
>>                  bh_unlock_sock(sk);
>> +               local_bh_enable();
>>          } else {
>> +               local_bh_disable();
>>                  sco_conn_lock(conn);
>>
>>                  if (!conn->hcon) {
>>                          sco_conn_unlock(conn);
>> +                       local_bh_enable();
>>                          return;
>>                  }
>>
>>                  parent = sco_get_sock_listen(&conn->hcon->src);
>>                  if (!parent) {
>>                          sco_conn_unlock(conn);
>> +                       local_bh_enable();
>>                          return;
>>                  }
>>
>> @@ -1109,6 +1131,7 @@ static void sco_conn_ready(struct sco_conn *conn)
>>                  if (!sk) {
>>                          bh_unlock_sock(parent);
>>                          sco_conn_unlock(conn);
>> +                       local_bh_enable();
>>                          return;
>>                  }
>>
>> @@ -1131,6 +1154,7 @@ static void sco_conn_ready(struct sco_conn *conn)
>>                  bh_unlock_sock(parent);
>>
>>                  sco_conn_unlock(conn);
>> +               local_bh_enable();
>>          }
>>   }
>>
>> --
>> 2.25.1
>>
> 
> 


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-07-15  2:21 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-13 16:28 [PATCH v2] Bluetooth: fix inconsistent lock state in sco Desmond Cheong Zhi Xi
2021-07-14 19:12 ` Luiz Augusto von Dentz
2021-07-15  2:21   ` Desmond Cheong Zhi Xi

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