Hello Luiz,
On 16.05.22 18:37, Ahmad Fatoum wrote:
>>>> - Commit a56a1138cbd8 ("Bluetooth: hci_sync: Fix not using conn_timeout")
>>>> fixes, despite the title, what event is waited on. First Pairing works now,
>>>> but the second pairing times out and crashes the kernel:
>>>>
>>>> [ 84.191684] Bluetooth: hci0: Opcode 0x200d failed: -110
>>>> [ 84.230478] Bluetooth: hci0: request failed to create LE connection: err -110
>>>> [ 84.237690] Unable to handle kernel read from unreadable memory at virtual address 0000000000000ca8
>>
>> That said the error -110 mean -ETIMEDOUT
>
> Yes, this issue remains still. I feel better about my revert
> knowing that the crash is fixed, but I'd like this regression
> here fixed upstream as well. I'll try to collect some more
> information and report back.
I've now found time to revisit this and sprinkle around some
extra logging. This is the initial pairing that works:
Bluetooth: entered hci_le_create_conn_sync()
Bluetooth: hci0: opcode 0x200d plen 25
Bluetooth: hci0: event 0x0f (sent = 0x0a)
Bluetooth: hci0: BT: opcode 0x200d (sent: 0x0a)
Bluetooth: hci0: event 0x3e (sent = 0x0a)
Bluetooth: hci0: BT: subevent 0x0a (sent 0x0a)
Bluetooth: entered hci_le_meta_evt(event=0x0a) completion clause
I unpaired on device side and then retried pairing:
Bluetooth: entered hci_le_create_conn_sync()
Bluetooth: hci0: opcode 0x200d plen 25
Bluetooth: hci0: event 0x0f (sent = 0x0a)
Bluetooth: hci0: BT: opcode 0x200d (sent: 0x0a)
Bluetooth: entered hci_abort_conn()
Bluetooth: hci0: opcode hci_req_add_ev 0x200e
Bluetooth: hci0: event 0x0e (sent = 0x00)
Bluetooth: hci0: event 0x3e (sent = 0x00)
Bluetooth: hci0: BT: subevent 0x0a (sent 0x00)
Bluetooth: __hci_cmd_sync_sk pending (event = 0x0a status=1, err=-110)
Bluetooth: hci0: Opcode 0x200d failed: -110
Bluetooth: hci0: opcode 0x2006 plen 15
Bluetooth: hci0: event 0x0e (sent = 0x00)
Bluetooth: hci0: opcode 0x200a plen 1
Bluetooth: hci0: event 0x0e (sent = 0x00)
Bluetooth: hci0: request failed to create LE connection: err -110
But now it times out as reported. It looks like the
intermittent hci_abort_conn() is at fault here. My theory is
that replacing hci->sent_cmd is the problem here, as other
events can't be matched anymore.
We've been deploying the revert for a while now and I just posted
it to the mailing list[1]. There have been other reports
of this issue with different hardware too and fixing sent_cmd
would likely be too complicated/time intensive for me.
I am happy to test future patches that fix this properly though.
[1]: https://lore.kernel.org/linux-bluetooth/20220616092418.738877-1-a.fatoum@xxxxxxxxxxxxxx/T/#t
Cheers,
Ahmad
>
> Cheers,
> Ahmad
>
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