Commit ab4eedb7 authored by Luiz Augusto von Dentz's avatar Luiz Augusto von Dentz
Browse files

Bluetooth: L2CAP: Fix corrupted list in hci_chan_del 



This fixes the following trace by reworking the locking of l2cap_conn
so instead of only locking when changing the chan_l list this promotes
chan_lock to a general lock of l2cap_conn so whenever it is being held
it would prevents the likes of l2cap_conn_del to run:

list_del corruption, ffff888021297e00->prev is LIST_POISON2 (dead000000000122)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:61!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 5896 Comm: syz-executor213 Not tainted 6.14.0-rc1-next-20250204-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:__list_del_entry_valid_or_report+0x12c/0x190 lib/list_debug.c:59
Code: 8c 4c 89 fe 48 89 da e8 32 8c 37 fc 90 0f 0b 48 89 df e8 27 9f 14 fd 48 c7 c7 a0 c0 60 8c 4c 89 fe 48 89 da e8 15 8c 37 fc 90 <0f> 0b 4c 89 e7 e8 0a 9f 14 fd 42 80 3c 2b 00 74 08 4c 89 e7 e8 cb
RSP: 0018:ffffc90003f6f998 EFLAGS: 00010246
RAX: 000000000000004e RBX: dead000000000122 RCX: 01454d423f7fbf00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff819f077c R09: 1ffff920007eded0
R10: dffffc0000000000 R11: fffff520007eded1 R12: dead000000000122
R13: dffffc0000000000 R14: ffff8880352248d8 R15: ffff888021297e00
FS:  00007f7ace6686c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7aceeeb1d0 CR3: 000000003527c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:124 [inline]
 __list_del_entry include/linux/list.h:215 [inline]
 list_del_rcu include/linux/rculist.h:168 [inline]
 hci_chan_del+0x70/0x1b0 net/bluetooth/hci_conn.c:2858
 l2cap_conn_free net/bluetooth/l2cap_core.c:1816 [inline]
 kref_put include/linux/kref.h:65 [inline]
 l2cap_conn_put+0x70/0xe0 net/bluetooth/l2cap_core.c:1830
 l2cap_sock_shutdown+0xa8a/0x1020 net/bluetooth/l2cap_sock.c:1377
 l2cap_sock_release+0x79/0x1d0 net/bluetooth/l2cap_sock.c:1416
 __sock_release net/socket.c:642 [inline]
 sock_close+0xbc/0x240 net/socket.c:1393
 __fput+0x3e9/0x9f0 fs/file_table.c:448
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 ptrace_notify+0x2d2/0x380 kernel/signal.c:2522
 ptrace_report_syscall include/linux/ptrace.h:415 [inline]
 ptrace_report_syscall_exit include/linux/ptrace.h:477 [inline]
 syscall_exit_work+0xc7/0x1d0 kernel/entry/common.c:173
 syscall_exit_to_user_mode_prepare kernel/entry/common.c:200 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:205 [inline]
 syscall_exit_to_user_mode+0x24a/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7aceeaf449
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7ace668218 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 00007f7acef39328 RCX: 00007f7aceeaf449
RDX: 000000000000000e RSI: 0000000020000100 RDI: 0000000000000004
RBP: 00007f7acef39320 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000004 R14: 00007f7ace668670 R15: 000000000000000b
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x12c/0x190 lib/list_debug.c:59
Code: 8c 4c 89 fe 48 89 da e8 32 8c 37 fc 90 0f 0b 48 89 df e8 27 9f 14 fd 48 c7 c7 a0 c0 60 8c 4c 89 fe 48 89 da e8 15 8c 37 fc 90 <0f> 0b 4c 89 e7 e8 0a 9f 14 fd 42 80 3c 2b 00 74 08 4c 89 e7 e8 cb
RSP: 0018:ffffc90003f6f998 EFLAGS: 00010246
RAX: 000000000000004e RBX: dead000000000122 RCX: 01454d423f7fbf00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff819f077c R09: 1ffff920007eded0
R10: dffffc0000000000 R11: fffff520007eded1 R12: dead000000000122
R13: dffffc0000000000 R14: ffff8880352248d8 R15: ffff888021297e00
FS:  00007f7ace6686c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7acef05b08 CR3: 000000003527c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Reported-by: default avatar <syzbot+10bd8fe6741eedd2be2e@syzkaller.appspotmail.com>
Tested-by: default avatar <syzbot+10bd8fe6741eedd2be2e@syzkaller.appspotmail.com>
Fixes: b4f82f9e ("Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd")
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
parent 872274b9

include/net/bluetooth/l2cap.h

+2 −1
Original line number Diff line number Diff line
@@ -668,7 +668,7 @@ struct l2cap_conn { 
	struct l2cap_chan	*smp;



	struct list_head	chan_l;

	struct mutex		chan_lock;

	struct mutex		lock;

	struct kref		ref;

	struct list_head	users;

};
@@ -970,6 +970,7 @@ void l2cap_chan_del(struct l2cap_chan *chan, int err); 
void l2cap_send_conn_req(struct l2cap_chan *chan);



struct l2cap_conn *l2cap_conn_get(struct l2cap_conn *conn);

struct l2cap_conn *l2cap_conn_hold_unless_zero(struct l2cap_conn *conn);

void l2cap_conn_put(struct l2cap_conn *conn);



int l2cap_register_user(struct l2cap_conn *conn, struct l2cap_user *user);

net/bluetooth/l2cap_core.c

+49 −89
Original line number Diff line number Diff line
@@ -119,7 +119,6 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, 
{

	struct l2cap_chan *c;



	mutex_lock(&conn->chan_lock);

	c = __l2cap_get_chan_by_scid(conn, cid);

	if (c) {

		/* Only lock if chan reference is not 0 */
@@ -127,7 +126,6 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, 
		if (c)

			l2cap_chan_lock(c);

	}

	mutex_unlock(&conn->chan_lock);



	return c;

}
@@ -140,7 +138,6 @@ static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn, 
{

	struct l2cap_chan *c;



	mutex_lock(&conn->chan_lock);

	c = __l2cap_get_chan_by_dcid(conn, cid);

	if (c) {

		/* Only lock if chan reference is not 0 */
@@ -148,7 +145,6 @@ static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn, 
		if (c)

			l2cap_chan_lock(c);

	}

	mutex_unlock(&conn->chan_lock);



	return c;

}
@@ -418,7 +414,7 @@ static void l2cap_chan_timeout(struct work_struct *work) 
	if (!conn)

		return;



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);

	/* __set_chan_timer() calls l2cap_chan_hold(chan) while scheduling

	 * this work. No need to call l2cap_chan_hold(chan) here again.

	 */
@@ -439,7 +435,7 @@ static void l2cap_chan_timeout(struct work_struct *work) 
	l2cap_chan_unlock(chan);

	l2cap_chan_put(chan);



	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

}



struct l2cap_chan *l2cap_chan_create(void)
@@ -641,9 +637,9 @@ void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan) 


void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)

{

	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);

	__l2cap_chan_add(conn, chan);

	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

}



void l2cap_chan_del(struct l2cap_chan *chan, int err)
@@ -731,9 +727,9 @@ void l2cap_chan_list(struct l2cap_conn *conn, l2cap_chan_func_t func, 
	if (!conn)

		return;



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);

	__l2cap_chan_list(conn, func, data);

	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

}



EXPORT_SYMBOL_GPL(l2cap_chan_list);
@@ -745,7 +741,7 @@ static void l2cap_conn_update_id_addr(struct work_struct *work) 
	struct hci_conn *hcon = conn->hcon;

	struct l2cap_chan *chan;



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);



	list_for_each_entry(chan, &conn->chan_l, list) {

		l2cap_chan_lock(chan);
@@ -754,7 +750,7 @@ static void l2cap_conn_update_id_addr(struct work_struct *work) 
		l2cap_chan_unlock(chan);

	}



	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

}



static void l2cap_chan_le_connect_reject(struct l2cap_chan *chan)
@@ -1507,8 +1503,6 @@ static void l2cap_conn_start(struct l2cap_conn *conn) 


	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);



	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {

		l2cap_chan_lock(chan);
@@ -1577,8 +1571,6 @@ static void l2cap_conn_start(struct l2cap_conn *conn) 


		l2cap_chan_unlock(chan);

	}



	mutex_unlock(&conn->chan_lock);

}



static void l2cap_le_conn_ready(struct l2cap_conn *conn)
@@ -1624,7 +1616,7 @@ static void l2cap_conn_ready(struct l2cap_conn *conn) 
	if (hcon->type == ACL_LINK)

		l2cap_request_info(conn);



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);



	list_for_each_entry(chan, &conn->chan_l, list) {
@@ -1642,7 +1634,7 @@ static void l2cap_conn_ready(struct l2cap_conn *conn) 
		l2cap_chan_unlock(chan);

	}



	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);



	if (hcon->type == LE_LINK)

		l2cap_le_conn_ready(conn);
@@ -1657,14 +1649,10 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err) 


	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);



	list_for_each_entry(chan, &conn->chan_l, list) {

		if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))

			l2cap_chan_set_err(chan, err);

	}



	mutex_unlock(&conn->chan_lock);

}



static void l2cap_info_timeout(struct work_struct *work)
@@ -1675,7 +1663,9 @@ static void l2cap_info_timeout(struct work_struct *work) 
	conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;

	conn->info_ident = 0;



	mutex_lock(&conn->lock);

	l2cap_conn_start(conn);

	mutex_unlock(&conn->lock);

}



/*
@@ -1767,6 +1757,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 


	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);



	mutex_lock(&conn->lock);



	kfree_skb(conn->rx_skb);



	skb_queue_purge(&conn->pending_rx);
@@ -1785,8 +1777,6 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 
	/* Force the connection to be immediately dropped */

	hcon->disc_timeout = 0;



	mutex_lock(&conn->chan_lock);



	/* Kill channels */

	list_for_each_entry_safe(chan, l, &conn->chan_l, list) {

		l2cap_chan_hold(chan);
@@ -1800,12 +1790,14 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 
		l2cap_chan_put(chan);

	}



	mutex_unlock(&conn->chan_lock);



	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)

		cancel_delayed_work_sync(&conn->info_timer);



	hci_chan_del(conn->hchan);

	conn->hchan = NULL;



	hcon->l2cap_data = NULL;

	mutex_unlock(&conn->lock);

	l2cap_conn_put(conn);

}
@@ -1813,7 +1805,6 @@ static void l2cap_conn_free(struct kref *ref) 
{

	struct l2cap_conn *conn = container_of(ref, struct l2cap_conn, ref);



	hci_chan_del(conn->hchan);

	hci_conn_put(conn->hcon);

	kfree(conn);

}
@@ -2924,8 +2915,6 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb) 


	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);



	list_for_each_entry(chan, &conn->chan_l, list) {

		if (chan->chan_type != L2CAP_CHAN_RAW)

			continue;
@@ -2940,8 +2929,6 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb) 
		if (chan->ops->recv(chan, nskb))

			kfree_skb(nskb);

	}



	mutex_unlock(&conn->chan_lock);

}



/* ---- L2CAP signalling commands ---- */
@@ -3960,7 +3947,6 @@ static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, 
		goto response;

	}



	mutex_lock(&conn->chan_lock);

	l2cap_chan_lock(pchan);



	/* Check if the ACL is secure enough (if not SDP) */
@@ -4067,7 +4053,6 @@ static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, 
	}



	l2cap_chan_unlock(pchan);

	mutex_unlock(&conn->chan_lock);

	l2cap_chan_put(pchan);

}
@@ -4106,27 +4091,19 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn, 
	BT_DBG("dcid 0x%4.4x scid 0x%4.4x result 0x%2.2x status 0x%2.2x",

	       dcid, scid, result, status);



	mutex_lock(&conn->chan_lock);



	if (scid) {

		chan = __l2cap_get_chan_by_scid(conn, scid);

		if (!chan) {

			err = -EBADSLT;

			goto unlock;

		}

		if (!chan)

			return -EBADSLT;

	} else {

		chan = __l2cap_get_chan_by_ident(conn, cmd->ident);

		if (!chan) {

			err = -EBADSLT;

			goto unlock;

		}

		if (!chan)

			return -EBADSLT;

	}



	chan = l2cap_chan_hold_unless_zero(chan);

	if (!chan) {

		err = -EBADSLT;

		goto unlock;

	}

	if (!chan)

		return -EBADSLT;



	err = 0;
@@ -4164,9 +4141,6 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn, 
	l2cap_chan_unlock(chan);

	l2cap_chan_put(chan);



unlock:

	mutex_unlock(&conn->chan_lock);



	return err;

}
@@ -4454,11 +4428,7 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, 


	chan->ops->set_shutdown(chan);



	l2cap_chan_unlock(chan);

	mutex_lock(&conn->chan_lock);

	l2cap_chan_lock(chan);

	l2cap_chan_del(chan, ECONNRESET);

	mutex_unlock(&conn->chan_lock);



	chan->ops->close(chan);
@@ -4495,11 +4465,7 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, 
		return 0;

	}



	l2cap_chan_unlock(chan);

	mutex_lock(&conn->chan_lock);

	l2cap_chan_lock(chan);

	l2cap_chan_del(chan, 0);

	mutex_unlock(&conn->chan_lock);



	chan->ops->close(chan);
@@ -4697,13 +4663,9 @@ static int l2cap_le_connect_rsp(struct l2cap_conn *conn, 
	BT_DBG("dcid 0x%4.4x mtu %u mps %u credits %u result 0x%2.2x",

	       dcid, mtu, mps, credits, result);



	mutex_lock(&conn->chan_lock);



	chan = __l2cap_get_chan_by_ident(conn, cmd->ident);

	if (!chan) {

		err = -EBADSLT;

		goto unlock;

	}

	if (!chan)

		return -EBADSLT;



	err = 0;
@@ -4751,9 +4713,6 @@ static int l2cap_le_connect_rsp(struct l2cap_conn *conn, 


	l2cap_chan_unlock(chan);



unlock:

	mutex_unlock(&conn->chan_lock);



	return err;

}
@@ -4865,7 +4824,6 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn, 
		goto response;

	}



	mutex_lock(&conn->chan_lock);

	l2cap_chan_lock(pchan);



	if (!smp_sufficient_security(conn->hcon, pchan->sec_level,
@@ -4931,7 +4889,6 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn, 


response_unlock:

	l2cap_chan_unlock(pchan);

	mutex_unlock(&conn->chan_lock);

	l2cap_chan_put(pchan);



	if (result == L2CAP_CR_PEND)
@@ -5065,7 +5022,6 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn, 
		goto response;

	}



	mutex_lock(&conn->chan_lock);

	l2cap_chan_lock(pchan);



	if (!smp_sufficient_security(conn->hcon, pchan->sec_level,
@@ -5140,7 +5096,6 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn, 


unlock:

	l2cap_chan_unlock(pchan);

	mutex_unlock(&conn->chan_lock);

	l2cap_chan_put(pchan);



response:
@@ -5177,8 +5132,6 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, 
	BT_DBG("mtu %u mps %u credits %u result 0x%4.4x", mtu, mps, credits,

	       result);



	mutex_lock(&conn->chan_lock);



	cmd_len -= sizeof(*rsp);



	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
@@ -5264,8 +5217,6 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, 
		l2cap_chan_unlock(chan);

	}



	mutex_unlock(&conn->chan_lock);



	return err;

}
@@ -5378,8 +5329,6 @@ static inline int l2cap_le_command_rej(struct l2cap_conn *conn, 
	if (cmd_len < sizeof(*rej))

		return -EPROTO;



	mutex_lock(&conn->chan_lock);



	chan = __l2cap_get_chan_by_ident(conn, cmd->ident);

	if (!chan)

		goto done;
@@ -5394,7 +5343,6 @@ static inline int l2cap_le_command_rej(struct l2cap_conn *conn, 
	l2cap_chan_put(chan);



done:

	mutex_unlock(&conn->chan_lock);

	return 0;

}
@@ -6849,8 +6797,12 @@ static void process_pending_rx(struct work_struct *work) 


	BT_DBG("");



	mutex_lock(&conn->lock);



	while ((skb = skb_dequeue(&conn->pending_rx)))

		l2cap_recv_frame(conn, skb);



	mutex_unlock(&conn->lock);

}



static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
@@ -6889,7 +6841,7 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) 
		conn->local_fixed_chan |= L2CAP_FC_SMP_BREDR;



	mutex_init(&conn->ident_lock);

	mutex_init(&conn->chan_lock);

	mutex_init(&conn->lock);



	INIT_LIST_HEAD(&conn->chan_l);

	INIT_LIST_HEAD(&conn->users);
@@ -7080,7 +7032,7 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, 
		}

	}



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);

	l2cap_chan_lock(chan);



	if (cid && __l2cap_get_chan_by_dcid(conn, cid)) {
@@ -7121,7 +7073,7 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, 


chan_unlock:

	l2cap_chan_unlock(chan);

	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

done:

	hci_dev_unlock(hdev);

	hci_dev_put(hdev);
@@ -7333,7 +7285,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt) 


	BT_DBG("conn %p status 0x%2.2x encrypt %u", conn, status, encrypt);



	mutex_lock(&conn->chan_lock);

	mutex_lock(&conn->lock);



	list_for_each_entry(chan, &conn->chan_l, list) {

		l2cap_chan_lock(chan);
@@ -7407,7 +7359,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt) 
		l2cap_chan_unlock(chan);

	}



	mutex_unlock(&conn->chan_lock);

	mutex_unlock(&conn->lock);

}



/* Append fragment into frame respecting the maximum len of rx_skb */
@@ -7474,8 +7426,11 @@ static void l2cap_recv_reset(struct l2cap_conn *conn) 
	conn->rx_len = 0;

}



static struct l2cap_conn *l2cap_conn_hold_unless_zero(struct l2cap_conn *c)

struct l2cap_conn *l2cap_conn_hold_unless_zero(struct l2cap_conn *c)

{

	if (!c)

		return NULL;



	BT_DBG("conn %p orig refcnt %u", c, kref_read(&c->ref));



	if (!kref_get_unless_zero(&c->ref))
@@ -7501,11 +7456,15 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags) 


	hci_dev_unlock(hcon->hdev);



	if (!conn)

		goto drop;

	if (!conn) {

		kfree_skb(skb);

		return;

	}



	BT_DBG("conn %p len %u flags 0x%x", conn, skb->len, flags);



	mutex_lock(&conn->lock);



	switch (flags) {

	case ACL_START:

	case ACL_START_NO_FLUSH:
@@ -7530,7 +7489,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags) 
		if (len == skb->len) {

			/* Complete frame received */

			l2cap_recv_frame(conn, skb);

			return;

			goto unlock;

		}



		BT_DBG("Start: total len %d, frag len %u", len, skb->len);
@@ -7592,10 +7551,11 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags) 
		break;

	}



	l2cap_conn_put(conn);



drop:

	kfree_skb(skb);

unlock:

	mutex_unlock(&conn->lock);

	l2cap_conn_put(conn);

}



static struct hci_cb l2cap_cb = {

net/bluetooth/l2cap_sock.c

+7 −8
Original line number Diff line number Diff line
@@ -1326,9 +1326,10 @@ static int l2cap_sock_shutdown(struct socket *sock, int how) 
	/* prevent sk structure from being freed whilst unlocked */

	sock_hold(sk);



	chan = l2cap_pi(sk)->chan;

	/* prevent chan structure from being freed whilst unlocked */

	l2cap_chan_hold(chan);

	chan = l2cap_chan_hold_unless_zero(l2cap_pi(sk)->chan);

	if (!chan)

		goto shutdown_already;



	BT_DBG("chan %p state %s", chan, state_to_string(chan->state));
@@ -1358,22 +1359,20 @@ static int l2cap_sock_shutdown(struct socket *sock, int how) 
	release_sock(sk);



	l2cap_chan_lock(chan);

	conn = chan->conn;

	if (conn)

	/* prevent conn structure from being freed */

		l2cap_conn_get(conn);

	conn = l2cap_conn_hold_unless_zero(chan->conn);

	l2cap_chan_unlock(chan);



	if (conn)

		/* mutex lock must be taken before l2cap_chan_lock() */

		mutex_lock(&conn->chan_lock);

		mutex_lock(&conn->lock);



	l2cap_chan_lock(chan);

	l2cap_chan_close(chan, 0);

	l2cap_chan_unlock(chan);



	if (conn) {

		mutex_unlock(&conn->chan_lock);

		mutex_unlock(&conn->lock);

		l2cap_conn_put(conn);

	}