Hi Jimmy,
On 11/19/19 4:53 AM, Jimmy Gysens wrote:
Hi,
After unplugging a Huawei USB dongle, the 'atoms' in oFono are removed via
'flush_atoms'.
Every atom has a destruct function pointer, used as a - yes - destructor.
When unplugging a dongle, connected via PPP, oFono will remove the current GPRS
context (= data connection).
The function calls are:
flush_atoms -> destruct -> gprs_context_remove -> at_gprs_context_remove ->
modem_disconnect
Because the device is physically removed, the IO channel for the AT port is
gone.
In 'at_gprs_context_remove', there is an attempt to resume communication over
that AT port, but that
is not possible. This is detected, and 'io_disconnect' (pointer to
'modem_disconnect') is called.
'modem_disconnect' has the same atom and tries to remove it again, so it calls
the same destructor.
modem_disconnect -> destruct -> gprs_context_remove -> at_gprs_context_remove
-> modem_disconnect
And the loop is started.
The easiest way to fix this, is to move the GPRS context removal. After a
disconnect, oFono tries to
re-open the AT port. If that fails (and it will in this case), we're done,
since 'modem_disconnect' returns.
In case the AT port can be opened, for example, when setting up a new
connection, the previous GPRS context
is removed.
The old GPRS context is removed via:
- 'flush_atoms' in case the USB device is physically removed.
- 'modem_disconnect' in case a new connection is being set up.
The loop hereby is fixed, without altering general functionality of oFono. This
fix is limited to Huawei devices and has been tested using the following
devices:
- E3531i-2
- E3372
- E3531s-2
- E369
- E1552
The patch itself:
---
ofono-1.31/plugins/huawei.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
Thanks for the detailed report! I went ahead and applied this fix
upstream after massaging the commit description a bit.
Regards,
-Denis
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