Currently there is no way to restart le scan, and it's needed in
service scan method. The way it work: it disable, and then enable le
scan on controller.
During the restart, we must remember when the scan was started, and
it's duration, to later re-schedule the le_scan_disable work, that was
stopped during the stop scan phase.
Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Instead of doing complex calculation every time the OOB data is used,
just calculate the OOB data present value and store it with the OOB
data raw values.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The smp_unregister() function needs to be called every time the
controller is powered down. There are multiple entry points when
this can happen. One is "hciconfig hci0 reset" which will throw
a WARN_ON when LE support has been enabled.
[ 78.564620] WARNING: CPU: 0 PID: 148 at net/bluetooth/smp.c:3075 smp_register+0xf1/0x170()
[ 78.564622] Modules linked in:
[ 78.564628] CPU: 0 PID: 148 Comm: kworker/u3:1 Not tainted 3.19.0-rc4-devel+ #404
[ 78.564629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
[ 78.564635] Workqueue: hci0 hci_rx_work
[ 78.564638] ffffffff81b4a7a2 ffff88001cb2fb38 ffffffff8161d881 0000000080000000
[ 78.564642] 0000000000000000 ffff88001cb2fb78 ffffffff8103b870 696e55206e6f6f6d
[ 78.564645] ffff88001d965000 0000000000000000 0000000000000000 ffff88001d965000
[ 78.564648] Call Trace:
[ 78.564655] [<ffffffff8161d881>] dump_stack+0x4f/0x7b
[ 78.564662] [<ffffffff8103b870>] warn_slowpath_common+0x80/0xc0
[ 78.564667] [<ffffffff81544b00>] ? add_uuid+0x1f0/0x1f0
[ 78.564671] [<ffffffff8103b955>] warn_slowpath_null+0x15/0x20
[ 78.564674] [<ffffffff81562d81>] smp_register+0xf1/0x170
[ 78.564680] [<ffffffff81081236>] ? lock_timer_base.isra.30+0x26/0x50
[ 78.564683] [<ffffffff81544bf0>] powered_complete+0xf0/0x120
[ 78.564688] [<ffffffff8152e622>] hci_req_cmd_complete+0x82/0x260
[ 78.564692] [<ffffffff8153554f>] hci_cmd_complete_evt+0x6cf/0x2e20
[ 78.564697] [<ffffffff81623e43>] ? _raw_spin_unlock_irqrestore+0x13/0x30
[ 78.564701] [<ffffffff8106b0af>] ? __wake_up_sync_key+0x4f/0x60
[ 78.564705] [<ffffffff8153a2ab>] hci_event_packet+0xbcb/0x2e70
[ 78.564709] [<ffffffff814094d3>] ? skb_release_all+0x23/0x30
[ 78.564711] [<ffffffff81409529>] ? kfree_skb+0x29/0x40
[ 78.564715] [<ffffffff815296c8>] hci_rx_work+0x1c8/0x3f0
[ 78.564719] [<ffffffff8105bd91>] ? get_parent_ip+0x11/0x50
[ 78.564722] [<ffffffff8105be25>] ? preempt_count_add+0x55/0xb0
[ 78.564727] [<ffffffff8104f65f>] process_one_work+0x12f/0x360
[ 78.564731] [<ffffffff8104ff9b>] worker_thread+0x6b/0x4b0
[ 78.564735] [<ffffffff8104ff30>] ? cancel_delayed_work_sync+0x10/0x10
[ 78.564738] [<ffffffff810542fa>] kthread+0xea/0x100
[ 78.564742] [<ffffffff81620000>] ? __schedule+0x3e0/0x980
[ 78.564745] [<ffffffff81054210>] ? kthread_create_on_node+0x180/0x180
[ 78.564749] [<ffffffff816246ec>] ret_from_fork+0x7c/0xb0
[ 78.564752] [<ffffffff81054210>] ? kthread_create_on_node+0x180/0x180
[ 78.564755] ---[ end trace 8b0d943af76d3736 ]---
This warning is not critical and has only been placed in the code to
actually catch this exact situation. To avoid triggering it move
the smp_unregister() into hci_dev_do_close() which will now also
take care of remove the SMP channel. It is safe to call this function
since it only remove the channel if it has been previously registered.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When receiving a HCI Hardware Error event, the controller should be
assumed to be non-functional until issuing a HCI Reset command.
The Bluetooth hardware errors are vendor specific and so add a
new hdev->hw_error callback that drivers can provide to run extra
code to handle the hardware error.
After completing the vendor specific error handling perform a full
reset of the Bluetooth stack by closing and re-opening the transport.
Based-on-patch-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Split the hci_dev_reset ioctl handling into using hci_dev_do_reset
helper function. Similar to what has been done with hci_dev_do_open
and hci_dev_do_close.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The discovery state should be set to stopped when the HCI device is
powered off. This patch adds the appropriate call to the
hci_discovery_set_state() function from hci_dev_do_close() which is
responsible for the power-off procedure.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The BR/EDR Secure Connections feature should only be enabled when the
Secure Simple Pairing mode has been enabled first. However since secure
connections is feature that is valid for BR/EDR and LE, this needs
special handling.
When enabling secure connections on a LE only configured controller,
thent the BR/EDR side should not be enabled in the controller. This
patches makes the BR/EDR Secure Connections feature depending on
enabling Secure Simple Pairing mode first.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the controller gets powered on via the management interface, then
register the supported SMP channels. There is no point in registering
these channels earlier since it is not know what identity address the
controller is going to operate with.
When powering down a controller unregister all SMP channels. This is
required since a powered down controller is allowed to change its
identity address.
In addition the SMP channels are only available when the controller
is powered via the management interface. When using legacy ioctl, then
Bluetooth Low Energy is not supported and registering kernel side SMP
integration may actually cause confusion.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This moves the execution of Delete Stored Link Key command to the
hci_init4_req phase. No actual code has been changed. The command
is just executed at a later stage of the initialization.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The information about max stored link keys and current stored link keys
should be read at controller initialization. So issue HCI Read Stored
Link Key command with BDADDR_ANY and read_all flag set to 0x01 to
retrieve this information.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When hci_req_run() calls its provided complete function and one of the
HCI commands in the sequence fails, then provide the opcode of failing
command. In case of success HCI_OP_NOP is provided since all commands
completed.
This patch fixes the prototype of hci_req_complete_t and all its users.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The HCI_QUIRK_FIXUP_INQUIRY_MODE option allows to force Inquiry Result
with RSSI setting on controllers that do not indicate support for it,
but where it is known to be fully functional.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
There are some old Bluetooth modules from Silicon Wave and Broadcom
which support Inquiry Result with RSSI, but do not advertise it. The
core has quirks in the code to enable that inquiry mode. However as
it stands right now, that code is not even executed since entering
the function to determine which inquiry mode requires that the device
has the feature bit for Inquiry Result with RSSI set in the first
place. So this makes this dead code that hasn't work for a long
time.
In conclusion, just remove these extra quirks and simplify the setup
of the inquiry mode to be inline and with that a lot easier to read
and understand.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the Bluetooth controllers requires an unconfigured state (for
example when the BD_ADDR is missing), then it is important to try
to register the SMP channels when the controller transitions to the
configured state.
This also fixes an issue with the debugfs entires that are not present
for controllers that start out as unconfigured.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The AVM BlueFritz! USB controllers had a special handling in the
Bluetooth core when it comes to reading the supported commands.
Both drivers now set the HCI_QUIRK_BROKEN_LOCAL_COMMANDS and with
that it is no longer needed to look for vendor specific details.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the controller supports the LE Data Length Extension feature, the
default and maximum data length are read and now stored.
For backwards compatibility all values are initialized to the data
length values from Bluetooth 4.1 and earlier specifications.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the controller supports the new LE Data Length Extension feature
from Bluetooth 4.2 specification, enable the new events and read the
values for default and maxmimum data length supported by the controller.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This patch moves the creation of the debugs files for LE controllers
into hci_debugfs.c file.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This patch moves the creation of the debugs files for BR/EDR controllers
into hci_debugfs.c file.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This patch moves the creation of the debugs files common for all
controllers into hci_debugfs.c file.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The debugfs file creation has been part of the core initialization
handling of controllers. With the introduction of Bluetooth 4.2 core
specification, the number of debugfs files is increasing even further.
To avoid cluttering the core controller handling, create a separate
file hci_debugfs.c to centralize all debugfs file creation. For now
leave the current files in the core, but in the future all debugfs
file creation will be moved.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Every BR/EDR/LE dual-mode controller requires to have a public address
and so far that has become the identity address and own address. The
only way to change that behavior was with a force_static_address
debugfs option.
However the host can actually disable the BR/EDR part of a dual-mode
controller and turn into a single mode LE controller. In that case
it makes perfect sense for a host to use a chosen static address
instead of the public address.
So if the host disables BR/EDR and configures a static address, then
that static address is used as identity address and own address. If
the host does not configure a static address, then the public address
is used as before.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This is a left-over from the patch that created hci_request.c. The
hci_update_page_scan functions should have been moved from hci_core.c
there.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch updates the Add Device mgmt command handler to use a
hci_request to wait for HCI command completion before notifying user
space of the mgmt command completion. To do this we need to add an extra
hci_request parameter to the hci_conn_params_set function. Since this
function has no other users besides mgmt.c it's moved there as a static
function.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Many places using hci_update_background_scan() try to synchronize
whatever they're doing with the help of hci_request callbacks. However,
since the hci_update_background_scan() function hasn't so far accepted a
hci_request pointer any commands triggered by it have been left out by
the synchronization. This patch modifies the API in a similar way as was
done for hci_update_page_scan, i.e. there's a variant that takes a
hci_request and another one that takes a hci_dev.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
None of the hci_request related things in net/bluetooth/hci_core.h are
needed anywhere outside of the core bluetooth module. This patch creates
a new net/bluetooth/hci_request.c file with its corresponding h-file and
moves the functionality there from hci_core.c and hci_core.h.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
To keep the parameter list and its semantics clear it makes sense to
split the hci_update_page_scan function into two separate functions: one
taking a hci_dev and another taking a hci_request. The one taking a
hci_dev constructs its own hci_request and then calls the other
function.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch moves the mgmt_powered() notification earlier in the
hci_dev_do_close() function. This way the correct "not powered" error
gets passed to any pending mgmt commands. Without the patch the pending
commands would instead get a misleading "disconnected" response when
powering down the adapter.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The Read Page Scan Activity and Read Page Scan Type commands are not
supported by all controllers. Move the execution of both commands
into the 3rd phase of the init procedure. And then check the bit
mask of supported commands before adding them to the init sequence.
With this re-ordering of the init sequence, the extra check for
AVM BlueFritz! controllers is no longer needed. They will report
that these two commands are not supported.
This fixes an issue with the Microsoft Corp. Wireless Transceiver
for Bluetooth 2.0 (ID 045e:009c).
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
mgmt_pending_remove() should be called with hci_dev_lock protection
and currently the rule to take dev lock is that all mgmt req_complete
functions should take dev lock. So this patch fixes the same in the
missing functions
Without this patch there is a chance of invalid memory access while
accessing the mgmt_pending list like below
bluetoothd: 392] [0] Backtrace:
bluetoothd: 392] [0] [<c04ec770>] (pending_eir_or_class+0x0/0x68) from [<c04f1830>] (add_uuid+0x34/0x1c4)
bluetoothd: 392] [0] [<c04f17fc>] (add_uuid+0x0/0x1c4) from [<c04f3cc4>] (mgmt_control+0x204/0x274)
bluetoothd: 392] [0] [<c04f3ac0>] (mgmt_control+0x0/0x274) from [<c04f609c>] (hci_sock_sendmsg+0x80/0x308)
bluetoothd: 392] [0] [<c04f601c>] (hci_sock_sendmsg+0x0/0x308) from [<c03d4d68>] (sock_aio_write+0x144/0x174)
bluetoothd: 392] [0] r8:00000000 r7 7c1be90 r6 7c1be18 r5:00000017 r4 a90ea80
bluetoothd: 392] [0] [<c03d4c24>] (sock_aio_write+0x0/0x174) from [<c00e2d4c>] (do_sync_write+0xb0/0xe0)
bluetoothd: 392] [0] [<c00e2c9c>] (do_sync_write+0x0/0xe0) from [<c00e371c>] (vfs_write+0x134/0x13c)
bluetoothd: 392] [0] r8:00000000 r7 7c1bf70 r6:beeca5c8 r5:00000017 r4 7c05900
bluetoothd: 392] [0] [<c00e35e8>] (vfs_write+0x0/0x13c) from [<c00e3910>] (sys_write+0x44/0x70)
bluetoothd: 392] [0] r8:00000000 r7:00000004 r6:00000017 r5:beeca5c8 r4 7c05900
bluetoothd: 392] [0] [<c00e38cc>] (sys_write+0x0/0x70) from [<c000e3c0>] (ret_fast_syscall+0x0/0x30)
bluetoothd: 392] [0] r9 7c1a000 r8:c000e568 r6:400b5f10 r5:403896d8 r4:beeca604
bluetoothd: 392] [0] Code: e28cc00c e152000c 0a00000f e3a00001 (e1d210b8)
bluetoothd: 392] [0] ---[ end trace 67b6ac67435864c4 ]---
bluetoothd: 392] [0] Kernel panic - not syncing: Fatal exception
Signed-off-by: Jaganath Kanakkassery <jaganath.k@samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
When the host decides to use a non-resolvable private address, it
must ensure that this generated address does not match the public
address of the controller. Add an extra check to ensure this required
behavior.
In addition rename the variable from urpa to nrpa and fix all of the
comments in the code that use the term unresolvable instead of the
term non-resolvable as used in the Bluetooth specification.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the LE Read Local P-256 Public Key command is supported, then
enable its corresponding complete event. And when the LE Generate DHKey
command is supported, enable its corresponding complete event as well.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The new Extended Scanner Filter Policies feature has to be enabled by
selecting the correct filter policy for the scan parameters. This
patch does that when the controller has been enabled to use LE Privacy.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When the controller supports the Extended Scanner Filter Policies, it
supports the LE Direct Advertising Report event. However by default
that event is blocked by the LE event mask. It is required to enable
it during controller setup.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Currently the discovery filter information are only cleared when the
actual discovery procedure has been stopped. To make sure that none
of the filters interfere with the background scanning and its device
found event reporting, clear the filter before starting background
scanning.
This means that the discovery filter is now cleared before either
Start Discovery, Start Service Discovery or background scanning.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
In case of failure or when unplugging a controller, the allocated
memory for the UUID list of the discovery filter is not freed. Use
the newly introduced helper for reset the discovery filter and with
that also freeing existing memory.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The discovery filter allocates memory for its UUID list. So use
a helper function to free it and reset it to default states.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
With the upcoming addition of support for Start Service Discovery, the
discovery handling needs to filter on RSSI and UUID values. For that
they need to be stored in the discovery handling. This patch adds the
appropiate fields and also make sure they are reset when discovery
has been stopped.
Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
We need to keep debug keys around at least until the point that they are
used - otherwise e.g. slave role behavior wouldn't work as there'd be no
key to be looked up. The correct behavior should therefore be to return
any stored keys but when we clean up the SMP context to remove the key
from the hdev list if keeping debug keys around hasn't been requestsed.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
To be able to support OOB data for LE pairing we need to store the
address type of the remote device. This patch extends the relevant
functions and data types with a bdaddr_type variable.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
There's no need to duplicate code for the 192 vs 192+256 variants of the
OOB data functions. This is also helpful to pave the way to support LE
SC OOB data where only 256 bit data is provided.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
To make it possible to use LE SC functionality over BR/EDR with pre-4.1
controllers (that do not support BR/EDR SC links) it's useful to be able
to force LE SC operations even over a traditional SSP protected link.
This patch adds a debugfs switch to force a special debug flag which is
used to skip the checks for BR/EDR SC support.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
We need to set the correct Link Key type based on the properties of the
LE SC pairing that it was derived from. If debug keys were used the type
should be a debug key, and the authenticated vs unauthenticated
information should be set on what kind of security level was reached.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that hci_find_ltk_by_addr is the only LTK lookup function there's no
need to keep the long name anymore. This patch shortens the function
name to simply hci_find_ltk.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that LTKs are always looked up based on bdaddr (with EDiv/Rand
checks done after a successful lookup) the hci_find_ltk function is not
needed anymore. This patch removes the function.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
LTKs derived from Secure Connections based pairing are symmetric, i.e.
they should match both master and slave role. This patch updates the LTK
lookup functions to ignore the desired role when dealing with SC LTKs.
Furthermore, with Secure Connections the EDiv and Rand values are not
used and should always be set to zero. This patch updates the LTK lookup
to first use the bdaddr as key and then do the necessary verifications
of EDiv and Rand based on whether the found LTK is for SC or not.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Since the HCI_SC_ENABLED flag will also be used for controllers without
BR/EDR Secure Connections support whenever we need to check specifically
for SC for BR/EDR we also need to check that the controller actually
supports it. This patch adds a convenience macro for check all the
necessary conditions and converts the places in the code that need it to
use it.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch converts the hdev->link_keys list to be protected through
RCU, thereby eliminating the need to hold the hdev lock while accessing
the list.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
In __hci_cmd_sync_ev() and __hci_req_sync() if the hci_req_run() call
fails and we return from the functions we should ensure that the state
doesn't remain in TASK_INTERRUPTIBLE that we just set it to. This patch
fixes missing calls to set_current_state(TASK_RUNNING) in both places.
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Doing things like hci_conn_hash_flush() while holding the hdev lock is
risky since its synchronous pending work cancellation could cause the
L2CAP layer to try to reacquire the hdev lock. Right now there doesn't
seem to be any obvious places where this would for certain happen but
it's already enough to cause lockdep to start warning against the hdev
and the work struct locks being taken in the "wrong" order:
[ +0.000373] mgmt-tester/1603 is trying to acquire lock:
[ +0.000292] ((&conn->pending_rx_work)){+.+.+.}, at: [<c104266d>] flush_work+0x0/0x181
[ +0.000270]
but task is already holding lock:
[ +0.000000] (&hdev->lock){+.+.+.}, at: [<c13b9a80>] hci_dev_do_close+0x166/0x359
[ +0.000000]
which lock already depends on the new lock.
[ +0.000000]
the existing dependency chain (in reverse order) is:
[ +0.000000]
-> #1 (&hdev->lock){+.+.+.}:
[ +0.000000] [<c105ea8f>] lock_acquire+0xe3/0x156
[ +0.000000] [<c140c663>] mutex_lock_nested+0x54/0x375
[ +0.000000] [<c13d644b>] l2cap_recv_frame+0x293/0x1a9c
[ +0.000000] [<c13d7ca4>] process_pending_rx+0x50/0x5e
[ +0.000000] [<c1041a3f>] process_one_work+0x21c/0x436
[ +0.000000] [<c1041e3d>] worker_thread+0x1be/0x251
[ +0.000000] [<c1045a22>] kthread+0x94/0x99
[ +0.000000] [<c140f801>] ret_from_kernel_thread+0x21/0x30
[ +0.000000]
-> #0 ((&conn->pending_rx_work)){+.+.+.}:
[ +0.000000] [<c105e158>] __lock_acquire+0xa07/0xc89
[ +0.000000] [<c105ea8f>] lock_acquire+0xe3/0x156
[ +0.000000] [<c1042696>] flush_work+0x29/0x181
[ +0.000000] [<c1042864>] __cancel_work_timer+0x76/0x8f
[ +0.000000] [<c104288c>] cancel_work_sync+0xf/0x11
[ +0.000000] [<c13d4c18>] l2cap_conn_del+0x72/0x183
[ +0.000000] [<c13d8953>] l2cap_disconn_cfm+0x49/0x55
[ +0.000000] [<c13be37a>] hci_conn_hash_flush+0x7a/0xc3
[ +0.000000] [<c13b9af6>] hci_dev_do_close+0x1dc/0x359
[ +0.012038] [<c13bbe38>] hci_unregister_dev+0x6e/0x1a3
[ +0.000000] [<c12d33c1>] vhci_release+0x28/0x47
[ +0.000000] [<c10dd6a9>] __fput+0xd6/0x154
[ +0.000000] [<c10dd757>] ____fput+0xd/0xf
[ +0.000000] [<c1044bb2>] task_work_run+0x6b/0x8d
[ +0.000000] [<c1001bd2>] do_notify_resume+0x3c/0x3f
[ +0.000000] [<c140fa70>] work_notifysig+0x29/0x31
[ +0.000000]
other info that might help us debug this:
[ +0.000000] Possible unsafe locking scenario:
[ +0.000000] CPU0 CPU1
[ +0.000000] ---- ----
[ +0.000000] lock(&hdev->lock);
[ +0.000000] lock((&conn->pending_rx_work));
[ +0.000000] lock(&hdev->lock);
[ +0.000000] lock((&conn->pending_rx_work));
[ +0.000000]
*** DEADLOCK ***
Fully fixing this would require some quite heavy refactoring to change
how the hdev lock and hci_conn instances are handled together. A simpler
solution for now which this patch takes is to try ensure that the hdev
workqueue is empty before proceeding with the various cleanup calls,
including hci_conn_hash_flush().
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
