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From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
To: marcel@holtmann.org, johan.hedberg@gmail.com,
	luiz.dentz@gmail.com, davem@davemloft.net, kuba@kernel.org,
	matthieu.baerts@tessares.net, stefan@datenfreihafen.org
Cc: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
	linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, skhan@linuxfoundation.org,
	gregkh@linuxfoundation.org,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH v3 2/2] Bluetooth: fix inconsistent lock state in rfcomm_connect_ind
Date: Wed, 21 Jul 2021 17:38:32 +0800	[thread overview]
Message-ID: <20210721093832.78081-3-desmondcheongzx@gmail.com> (raw)
In-Reply-To: <20210721093832.78081-1-desmondcheongzx@gmail.com>

Commit fad003b6c8e3d ("Bluetooth: Fix inconsistent lock state with
RFCOMM") fixed a lockdep warning due to sk->sk_lock.slock being
acquired without disabling softirq while the lock is also used in
softirq context. This was done by disabling interrupts before calling
bh_lock_sock in rfcomm_sk_state_change.

Later, this was changed in commit e6da0edc24ee ("Bluetooth: Acquire
sk_lock.slock without disabling interrupts") to disable softirqs
only.

However, there is another instance of sk->sk_lock.slock being acquired
without disabling softirq in rfcomm_connect_ind. This patch fixes this
by disabling local bh before the call to bh_lock_sock.

Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
---
 net/bluetooth/rfcomm/sock.c | 2 ++
 1 file changed, 2 insertions(+)

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);
-- 
2.25.1


  parent reply	other threads:[~2021-07-21  9:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-21  9:38 [PATCH v3 0/2] Bluetooth: fix inconsistent lock states Desmond Cheong Zhi Xi
2021-07-21  9:38 ` [PATCH v3 1/2] Bluetooth: fix inconsistent lock state in SCO Desmond Cheong Zhi Xi
2021-07-27  0:30   ` Luiz Augusto von Dentz
2021-07-27  5:13     ` Desmond Cheong Zhi Xi
2021-07-21  9:38 ` Desmond Cheong Zhi Xi [this message]
2021-07-29 19:53   ` [PATCH v3 2/2] Bluetooth: fix inconsistent lock state in rfcomm_connect_ind Marcel Holtmann
2021-07-30  9:06     ` Desmond Cheong Zhi Xi
2021-07-30 13:40       ` Marcel Holtmann

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