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 01f9316b4c23..1224bba24bdd 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 v1.2.2 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 +++-- 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'include/net/bluetooth') diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h index f69f015bbcc0..ed3aea1605e8 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 1224bba24bdd..be5bd713d2c9 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 -- cgit v1.2.2 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 + 1 file changed, 1 insertion(+) (limited to 'include/net/bluetooth') diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index be5bd713d2c9..73aead222b32 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); -- cgit v1.2.2