From f3784d834c71689336fa272df420b45345cb6b84 Mon Sep 17 00:00:00 2001 From: Roger Quadros Date: Thu, 23 Apr 2009 14:50:54 +0300 Subject: Bluetooth: Ensure that HCI sysfs add/del is preempt safe Use a different work_struct variables for add_conn() and del_conn() and use single work queue instead of two for adding and deleting connections. It eliminates the following error on a preemptible kernel: [ 204.358032] Unable to handle kernel NULL pointer dereference at virtual address 0000000c [ 204.370697] pgd = c0004000 [ 204.373443] [0000000c] *pgd=00000000 [ 204.378601] Internal error: Oops: 17 [#1] PREEMPT [ 204.383361] Modules linked in: vfat fat rfcomm sco l2cap sd_mod scsi_mod iphb pvr2d drm omaplfb ps [ 204.438537] CPU: 0 Not tainted (2.6.28-maemo2 #1) [ 204.443664] PC is at klist_put+0x2c/0xb4 [ 204.447601] LR is at klist_put+0x18/0xb4 [ 204.451568] pc : [] lr : [] psr: a0000113 [ 204.451568] sp : cf1b3f10 ip : cf1b3f10 fp : cf1b3f2c [ 204.463104] r10: 00000000 r9 : 00000000 r8 : bf08029c [ 204.468353] r7 : c7869200 r6 : cfbe2690 r5 : c78692c8 r4 : 00000001 [ 204.474945] r3 : 00000001 r2 : cf1b2000 r1 : 00000001 r0 : 00000000 [ 204.481506] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel [ 204.488861] Control: 10c5387d Table: 887fc018 DAC: 00000017 [ 204.494628] Process btdelconn (pid: 515, stack limit = 0xcf1b22e0) Signed-off-by: Roger Quadros Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci_core.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/net/bluetooth') diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 01f9316b4c2..1224bba24bd 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -180,7 +180,8 @@ struct hci_conn { struct timer_list disc_timer; struct timer_list idle_timer; - struct work_struct work; + struct work_struct work_add; + struct work_struct work_del; struct device dev; -- cgit v1.2.3-70-g09d2 From 052b30b0a8eec8db5b18ad49effdf2a9ba4c1e1a Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Sun, 26 Apr 2009 20:01:22 +0200 Subject: Bluetooth: Add different pairing timeout for Legacy Pairing The Bluetooth stack uses a reference counting for all established ACL links and if no user (L2CAP connection) is present, the link will be terminated to save power. The problem part is the dedicated pairing when using Legacy Pairing (Bluetooth 2.0 and before). At that point no user is present and pairing attempts will be disconnected within 10 seconds or less. In previous kernel version this was not a problem since the disconnect timeout wasn't triggered on incoming connections for the first time. However this caused issues with broken host stacks that kept the connections around after dedicated pairing. When the support for Simple Pairing got added, the link establishment procedure needed to be changed and now causes issues when using Legacy Pairing When using Simple Pairing it is possible to do a proper reference counting of ACL link users. With Legacy Pairing this is not possible since the specification is unclear in some areas and too many broken Bluetooth devices have already been deployed. So instead of trying to deal with all the broken devices, a special pairing timeout will be introduced that increases the timeout to 60 seconds when pairing is triggered. If a broken devices now puts the stack into an unforeseen state, the worst that happens is the disconnect timeout triggers after 120 seconds instead of 4 seconds. This allows successful pairings with legacy and broken devices now. Based on a report by Johan Hedberg Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci.h | 1 + include/net/bluetooth/hci_core.h | 5 +++-- net/bluetooth/hci_conn.c | 1 + net/bluetooth/hci_event.c | 36 +++++++++++++++++++++++++++++++++++- 4 files changed, 40 insertions(+), 3 deletions(-) (limited to 'include/net/bluetooth') diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h index f69f015bbcc..ed3aea1605e 100644 --- a/include/net/bluetooth/hci.h +++ b/include/net/bluetooth/hci.h @@ -101,6 +101,7 @@ enum { /* HCI timeouts */ #define HCI_CONNECT_TIMEOUT (40000) /* 40 seconds */ #define HCI_DISCONN_TIMEOUT (2000) /* 2 seconds */ +#define HCI_PAIRING_TIMEOUT (60000) /* 60 seconds */ #define HCI_IDLE_TIMEOUT (6000) /* 6 seconds */ #define HCI_INIT_TIMEOUT (10000) /* 10 seconds */ diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 1224bba24bd..be5bd713d2c 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -171,6 +171,7 @@ struct hci_conn { __u8 auth_type; __u8 sec_level; __u8 power_save; + __u16 disc_timeout; unsigned long pend; unsigned int sent; @@ -349,9 +350,9 @@ static inline void hci_conn_put(struct hci_conn *conn) if (conn->type == ACL_LINK) { del_timer(&conn->idle_timer); if (conn->state == BT_CONNECTED) { - timeo = msecs_to_jiffies(HCI_DISCONN_TIMEOUT); + timeo = msecs_to_jiffies(conn->disc_timeout); if (!conn->out) - timeo *= 5; + timeo *= 2; } else timeo = msecs_to_jiffies(10); } else diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 1181db08d9d..75ebbe2221a 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -215,6 +215,7 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst) conn->state = BT_OPEN; conn->power_save = 1; + conn->disc_timeout = HCI_DISCONN_TIMEOUT; switch (type) { case ACL_LINK: diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 15f40ea8d54..4e7cb88e5da 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -883,6 +883,7 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s if (conn->type == ACL_LINK) { conn->state = BT_CONFIG; hci_conn_hold(conn); + conn->disc_timeout = HCI_DISCONN_TIMEOUT; } else conn->state = BT_CONNECTED; @@ -1063,9 +1064,14 @@ static inline void hci_auth_complete_evt(struct hci_dev *hdev, struct sk_buff *s hci_proto_connect_cfm(conn, ev->status); hci_conn_put(conn); } - } else + } else { hci_auth_cfm(conn, ev->status); + hci_conn_hold(conn); + conn->disc_timeout = HCI_DISCONN_TIMEOUT; + hci_conn_put(conn); + } + if (test_bit(HCI_CONN_ENCRYPT_PEND, &conn->pend)) { if (!ev->status) { struct hci_cp_set_conn_encrypt cp; @@ -1479,7 +1485,21 @@ static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb static inline void hci_pin_code_request_evt(struct hci_dev *hdev, struct sk_buff *skb) { + struct hci_ev_pin_code_req *ev = (void *) skb->data; + struct hci_conn *conn; + BT_DBG("%s", hdev->name); + + hci_dev_lock(hdev); + + conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &ev->bdaddr); + if (conn) { + hci_conn_hold(conn); + conn->disc_timeout = HCI_PAIRING_TIMEOUT; + hci_conn_put(conn); + } + + hci_dev_unlock(hdev); } static inline void hci_link_key_request_evt(struct hci_dev *hdev, struct sk_buff *skb) @@ -1489,7 +1509,21 @@ static inline void hci_link_key_request_evt(struct hci_dev *hdev, struct sk_buff static inline void hci_link_key_notify_evt(struct hci_dev *hdev, struct sk_buff *skb) { + struct hci_ev_link_key_notify *ev = (void *) skb->data; + struct hci_conn *conn; + BT_DBG("%s", hdev->name); + + hci_dev_lock(hdev); + + conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &ev->bdaddr); + if (conn) { + hci_conn_hold(conn); + conn->disc_timeout = HCI_DISCONN_TIMEOUT; + hci_conn_put(conn); + } + + hci_dev_unlock(hdev); } static inline void hci_clock_offset_evt(struct hci_dev *hdev, struct sk_buff *skb) -- cgit v1.2.3-70-g09d2 From a67e899cf38ae542d1a028ccd021f9189f76fb74 Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Sat, 2 May 2009 18:24:06 -0700 Subject: Bluetooth: Fix issue with sysfs handling for connections Due to a semantic changes in flush_workqueue() the current approach of synchronizing the sysfs handling for connections doesn't work anymore. The whole approach is actually fully broken and based on assumptions that are no longer valid. With the introduction of Simple Pairing support, the creation of low-level ACL links got changed. This change invalidates the reason why in the past two independent work queues have been used for adding/removing sysfs devices. The adding of the actual sysfs device is now postponed until the host controller successfully assigns an unique handle to that link. So the real synchronization happens inside the controller and not the host. The only left-over problem is that some internals of the sysfs device handling are not initialized ahead of time. This leaves potential access to invalid data and can cause various NULL pointer dereferences. To fix this a new function makes sure that all sysfs details are initialized when an connection attempt is made. The actual sysfs device is only registered when the connection has been successfully established. To avoid a race condition with the registration, the check if a device is registered has been moved into the removal work. As an extra protection two flush_work() calls are left in place to make sure a previous add/del work has been completed first. Based on a report by Marc Pignat Signed-off-by: Marcel Holtmann Tested-by: Justin P. Mattock Tested-by: Roger Quadros Tested-by: Marc Pignat --- include/net/bluetooth/hci_core.h | 1 + net/bluetooth/hci_conn.c | 2 ++ net/bluetooth/hci_sysfs.c | 74 ++++++++++++++++++++++------------------ 3 files changed, 43 insertions(+), 34 deletions(-) (limited to 'include/net/bluetooth') diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index be5bd713d2c..73aead222b3 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -457,6 +457,7 @@ int hci_recv_fragment(struct hci_dev *hdev, int type, void *data, int count); int hci_register_sysfs(struct hci_dev *hdev); void hci_unregister_sysfs(struct hci_dev *hdev); +void hci_conn_init_sysfs(struct hci_conn *conn); void hci_conn_add_sysfs(struct hci_conn *conn); void hci_conn_del_sysfs(struct hci_conn *conn); diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 375f4b4f7f7..61309b26f27 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -248,6 +248,8 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst) if (hdev->notify) hdev->notify(hdev, HCI_NOTIFY_CONN_ADD); + hci_conn_init_sysfs(conn); + tasklet_enable(&hdev->tx_task); return conn; diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c index b7c51082dde..582d8877078 100644 --- a/net/bluetooth/hci_sysfs.c +++ b/net/bluetooth/hci_sysfs.c @@ -9,7 +9,7 @@ struct class *bt_class = NULL; EXPORT_SYMBOL_GPL(bt_class); -static struct workqueue_struct *bluetooth; +static struct workqueue_struct *bt_workq; static inline char *link_typetostr(int type) { @@ -89,8 +89,8 @@ static void add_conn(struct work_struct *work) { struct hci_conn *conn = container_of(work, struct hci_conn, work_add); - /* ensure previous add/del is complete */ - flush_workqueue(bluetooth); + /* ensure previous del is complete */ + flush_work(&conn->work_del); if (device_add(&conn->dev) < 0) { BT_ERR("Failed to register connection device"); @@ -98,27 +98,6 @@ static void add_conn(struct work_struct *work) } } -void hci_conn_add_sysfs(struct hci_conn *conn) -{ - struct hci_dev *hdev = conn->hdev; - - BT_DBG("conn %p", conn); - - conn->dev.type = &bt_link; - conn->dev.class = bt_class; - conn->dev.parent = &hdev->dev; - - dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle); - - dev_set_drvdata(&conn->dev, conn); - - device_initialize(&conn->dev); - - INIT_WORK(&conn->work_add, add_conn); - - queue_work(bluetooth, &conn->work_add); -} - /* * The rfcomm tty device will possibly retain even when conn * is down, and sysfs doesn't support move zombie device, @@ -134,8 +113,11 @@ static void del_conn(struct work_struct *work) struct hci_conn *conn = container_of(work, struct hci_conn, work_del); struct hci_dev *hdev = conn->hdev; - /* ensure previous add/del is complete */ - flush_workqueue(bluetooth); + /* ensure previous add is complete */ + flush_work(&conn->work_add); + + if (!device_is_registered(&conn->dev)) + return; while (1) { struct device *dev; @@ -152,16 +134,40 @@ static void del_conn(struct work_struct *work) hci_dev_put(hdev); } -void hci_conn_del_sysfs(struct hci_conn *conn) +void hci_conn_init_sysfs(struct hci_conn *conn) { + struct hci_dev *hdev = conn->hdev; + BT_DBG("conn %p", conn); - if (!device_is_registered(&conn->dev)) - return; + conn->dev.type = &bt_link; + conn->dev.class = bt_class; + conn->dev.parent = &hdev->dev; + + dev_set_drvdata(&conn->dev, conn); + device_initialize(&conn->dev); + + INIT_WORK(&conn->work_add, add_conn); INIT_WORK(&conn->work_del, del_conn); +} + +void hci_conn_add_sysfs(struct hci_conn *conn) +{ + struct hci_dev *hdev = conn->hdev; + + BT_DBG("conn %p", conn); + + dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle); + + queue_work(bt_workq, &conn->work_add); +} + +void hci_conn_del_sysfs(struct hci_conn *conn) +{ + BT_DBG("conn %p", conn); - queue_work(bluetooth, &conn->work_del); + queue_work(bt_workq, &conn->work_del); } static inline char *host_typetostr(int type) @@ -438,13 +444,13 @@ void hci_unregister_sysfs(struct hci_dev *hdev) int __init bt_sysfs_init(void) { - bluetooth = create_singlethread_workqueue("bluetooth"); - if (!bluetooth) + bt_workq = create_singlethread_workqueue("bluetooth"); + if (!bt_workq) return -ENOMEM; bt_class = class_create(THIS_MODULE, "bluetooth"); if (IS_ERR(bt_class)) { - destroy_workqueue(bluetooth); + destroy_workqueue(bt_workq); return PTR_ERR(bt_class); } @@ -453,7 +459,7 @@ int __init bt_sysfs_init(void) void bt_sysfs_cleanup(void) { - destroy_workqueue(bluetooth); + destroy_workqueue(bt_workq); class_destroy(bt_class); } -- cgit v1.2.3-70-g09d2