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In-Reply-To: <CAHotPr9pgFt6URGN4ZUqngtQAijsGy_7uESibAAnmLSdagv6pA@mail.gmail.com>
From:   Gal Ben Haim <gbenhaim@augury.com>
Date:   Tue, 5 Feb 2019 09:11:47 +0200
Message-ID: <CAHotPr8RW+_=yhdZKE8XJMoq2sFM3PqZR2mL6ixuom8LUzOkDw@mail.gmail.com>
Subject: Re: [PATCH BlueZ 1/5] gatt: Fix invalid read when disconnecting
To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     linux-bluetooth@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-bluetooth-owner@vger.kernel.org
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I didn't get to it... with the current patch BlueZ definitely crashes,
but this is without newer patches if anything related was changed.

On Sun, Jan 6, 2019 at 11:04 AM Gal Ben Haim <gbenhaim@augury.com> wrote:
>
> Yes, it is with GATT caching enabled. However, we are deleting the device on disconnection, if its related...
>
> It will take me some time to get to Valgrind.
>
> On Tue, Jan 1, 2019, 21:27 Luiz Augusto von Dentz <luiz.dentz@gmail.com wrote:
>>
>> Hi Gal,
>>
>> On Sat, Dec 22, 2018 at 3:51 PM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> >
>> > it definitely happens with this patch and not with mine
>>
>> Can you try with valgrind so we got to see if the backtrace is really
>> the same, also is that using GATT caching or is that disabled?
>>
>> > On Sat, Dec 15, 2018 at 8:45 AM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> > >
>> > > I still get segmentation faults occasionally after applying this patch,
>> > > i'm not 100% sure that it's related but it happens in the same area...
>> > > its not something that I can reproduce immediately like with the
>> > > previous segfault. I think that it doesn't happen if I use my original
>> > > patch https://marc.info/?l=linux-bluetooth&m=154250398526173&w=2
>> > >
>> > > bluetoothd[2599]: src/device.c:att_disconnected_cb()
>> > > bluetoothd[2599]: src/device.c:att_disconnected_cb() Connection reset
>> > > by peer (104)
>> > > bluetoothd[2599]: src/service.c:change_state() 0x4edae0: device
>> > > DA:51:61:24:3C:36 profile gap-profile state changed: connected ->
>> > > disconnecting (0)
>> > > bluetoothd[2599]: src/service.c:change_state() 0x4edae0: device
>> > > DA:51:61:24:3C:36 profile gap-profile state changed: disconnecting ->
>> > > disconnected (0)
>> > > bluetoothd[2599]: src/gatt-client.c:btd_gatt_client_disconnected()
>> > > Device disconnected. Cleaning up.
>> > > bluetoothd[2599]: src/device.c:att_disconnected_cb() Automatic
>> > > connection disabled
>> > > bluetoothd[2599]: src/gatt-database.c:btd_gatt_database_att_disconnected()
>> > > bluetoothd[2599]: attrib/gattrib.c:g_attrib_unref() 0x4ee410: g_attrib_unref=0
>> > > bluetoothd[2599]: src/device.c:btd_device_set_temporary() temporary 1
>> > > bluetoothd[2599]: src/device.c:device_remove() Removing device
>> > > /org/bluez/hci0/dev_DA_51_61_24_3C_36
>> > > bluetoothd[2599]: src/service.c:change_state() 0x4edae0: device
>> > > DA:51:61:24:3C:36 profile gap-profile state changed: disconnected ->
>> > > unavailable (0)
>> > > bluetoothd[2599]: profiles/gap/gas.c:gap_remove() GAP profile remove
>> > > (DA:51:61:24:3C:36)
>> > > bluetoothd[2599]: src/service.c:btd_service_unref() 0x4edae0: ref=0
>> > > bluetoothd[2599]: src/device.c:btd_device_unref() Freeing device
>> > > /org/bluez/hci0/dev_DA_51_61_24_3C_36
>> > > bluetoothd[2599]: src/gatt-client.c:unregister_service() Removing GATT
>> > > service: /org/bluez/hci0/dev_DA_51_61_24_3C_36/service0008
>> > > bluetoothd[2599]: src/gatt-client.c:unregister_service() Removing GATT
>> > > service: /org/bluez/hci0/dev_DA_51_61_24_3C_36/service0009
>> > > bluetoothd[2599]: src/gatt-client.c:unregister_characteristic()
>> > > Removing GATT characteristic:
>> > > /org/bluez/hci0/dev_DA_51_61_24_3C_36/service0009/char000a
>> > > bluetoothd[2599]: src/gatt-client.c:unregister_characteristic()
>> > > Removing GATT characteristic:
>> > > /org/bluez/hci0/dev_DA_51_61_24_3C_36/service0009/char000c
>> > > bluetoothd[2599]: src/gatt-client.c:unregister_descriptor() Removing
>> > > GATT descriptor:
>> > > /org/bluez/hci0/dev_DA_51_61_24_3C_36/service0009/char000c/desc000e
>> > > Segmentation fault
>> > >
>> > >
>> > > On Wed, Nov 21, 2018 at 11:15 AM Luiz Augusto von Dentz
>> > > <luiz.dentz@gmail.com> wrote:
>> > > >
>> > > > Hi,
>> > > > On Wed, Nov 21, 2018 at 9:15 AM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> > > > >
>> > > > > it fixes the same case that cause the version from master to crash.
>> > > > > i haven't tested for anything else..
>> > > > >
>> > > > > On Tue, Nov 20, 2018 at 8:31 PM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> > > > > >
>> > > > > > ok I patched it. i'll test it tomorrow in the office and let you know.
>> > > > > >
>> > > > > > On Tue, Nov 20, 2018 at 3:59 PM Luiz Augusto von Dentz
>> > > > > > <luiz.dentz@gmail.com> wrote:
>> > > > > > >
>> > > > > > > Hi Gal,
>> > > > > > >
>> > > > > > > On Tue, Nov 20, 2018 at 2:35 PM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> > > > > > > >
>> > > > > > > > i tried with both git am and git apply
>> > > > > > >
>> > > > > > > Does that applies to v2 as well? I just rebased it on top master, are
>> > > > > > > you sure you don't have your own changes conflicting with it?
>> > > > > > >
>> > > > > > > > On Tue, Nov 20, 2018 at 12:35 PM Luiz Augusto von Dentz
>> > > > > > > > <luiz.dentz@gmail.com> wrote:
>> > > > > > > > >
>> > > > > > > > > Hi Gal,
>> > > > > > > > > On Tue, Nov 20, 2018 at 11:31 AM Gal Ben Haim <gbenhaim@augury.com> wrote:
>> > > > > > > > > >
>> > > > > > > > > > I can't apply this patch, not to the revision in master and not to the 5.50 tag
>> > > > > > > > >
>> > > > > > > > > They are on top o master, how are you trying to apply them, with git am?
>> > > > > > > > >
>> > > > > > > > > > On Tue, Nov 20, 2018 at 10:50 AM Luiz Augusto von Dentz
>> > > > > > > > > > <luiz.dentz@gmail.com> wrote:
>> > > > > > > > > > >
>> > > > > > > > > > > On Mon, Nov 19, 2018 at 5:43 PM Luiz Augusto von Dentz
>> > > > > > > > > > > <luiz.dentz@gmail.com> wrote:
>> > > > > > > > > > > >
>> > > > > > > > > > > > From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>> > > > > > > > > > > >
>> > > > > > > > > > > > In case there is a client of AcquireNotify and a disconnect happens the
>> > > > > > > > > > > > code not only have to free the client object but also destroy the io
>> > > > > > > > > > > > associated with it, for this reason the client object cannot be freed
>> > > > > > > > > > > > until the io is destroyed otherwise it may lead to the following error:
>> > > > > > > > > > > >
>> > > > > > > > > > > > Invalid read of size 4
>> > > > > > > > > > > >    at 0x63920: notify_io_destroy (gatt-client.c:1461)
>> > > > > > > > > > > >    by 0x63EDB: pipe_io_destroy (gatt-client.c:1082)
>> > > > > > > > > > > >    by 0x6405B: characteristic_free (gatt-client.c:1663)
>> > > > > > > > > > > >    by 0x81F33: remove_interface (object.c:667)
>> > > > > > > > > > > >    by 0x826CB: g_dbus_unregister_interface (object.c:1391)
>> > > > > > > > > > > >    by 0x85D2B: queue_remove_all (queue.c:354)
>> > > > > > > > > > > >    by 0x635F7: unregister_service (gatt-client.c:1893)
>> > > > > > > > > > > >    by 0x85CF7: queue_remove_all (queue.c:339)
>> > > > > > > > > > > >    by 0x661DF: btd_gatt_client_service_removed (gatt-client.c:2199)
>> > > > > > > > > > > >    by 0x695CB: gatt_service_removed (device.c:3747)
>> > > > > > > > > > > >    by 0x85B17: queue_foreach (queue.c:220)
>> > > > > > > > > > > >    by 0x91283: notify_service_changed (gatt-db.c:280)
>> > > > > > > > > > > >    by 0x91283: gatt_db_service_destroy (gatt-db.c:291)
>> > > > > > > > > > > >  Address 0x515ed48 is 0 bytes inside a block of size 20 free'd
>> > > > > > > > > > > >    at 0x483EAD0: free (vg_replace_malloc.c:530)
>> > > > > > > > > > > >    by 0x85D2B: queue_remove_all (queue.c:354)
>> > > > > > > > > > > >    by 0x636D3: unregister_characteristic (gatt-client.c:1741)
>> > > > > > > > > > > >    by 0x85D2B: queue_remove_all (queue.c:354)
>> > > > > > > > > > > >    by 0x635F7: unregister_service (gatt-client.c:1893)
>> > > > > > > > > > > >    by 0x85CF7: queue_remove_all (queue.c:339)
>> > > > > > > > > > > >    by 0x661DF: btd_gatt_client_service_removed (gatt-client.c:2199)
>> > > > > > > > > > > >    by 0x695CB: gatt_service_removed (device.c:3747)
>> > > > > > > > > > > >    by 0x85B17: queue_foreach (queue.c:220)
>> > > > > > > > > > > >    by 0x91283: notify_service_changed (gatt-db.c:280)
>> > > > > > > > > > > >    by 0x91283: gatt_db_service_destroy (gatt-db.c:291)
>> > > > > > > > > > > >    by 0x85D2B: queue_remove_all (queue.c:354)
>> > > > > > > > > > > >    by 0x91387: gatt_db_clear_range (gatt-db.c:475)
>> > > > > > > > > > > > ---
>> > > > > > > > > > > >  src/gatt-client.c | 24 ++++++++++++------------
>> > > > > > > > > > > >  1 file changed, 12 insertions(+), 12 deletions(-)
>> > > > > > > > > > > >
>> > > > > > > > > > > > diff --git a/src/gatt-client.c b/src/gatt-client.c
>> > > > > > > > > > > > index 234f46ed7..55aa5e423 100644
>> > > > > > > > > > > > --- a/src/gatt-client.c
>> > > > > > > > > > > > +++ b/src/gatt-client.c
>> > > > > > > > > > > > @@ -1645,13 +1645,22 @@ static const GDBusMethodTable characteristic_methods[] = {
>> > > > > > > > > > > >         { }
>> > > > > > > > > > > >  };
>> > > > > > > > > > > >
>> > > > > > > > > > > > +static void remove_client(void *data)
>> > > > > > > > > > > > +{
>> > > > > > > > > > > > +       struct notify_client *ntfy_client = data;
>> > > > > > > > > > > > +       struct btd_gatt_client *client = ntfy_client->chrc->service->client;
>> > > > > > > > > > > > +
>> > > > > > > > > > > > +       queue_remove(client->all_notify_clients, ntfy_client);
>> > > > > > > > > > > > +
>> > > > > > > > > > > > +       notify_client_unref(ntfy_client);
>> > > > > > > > > > > > +}
>> > > > > > > > > > > > +
>> > > > > > > > > > > >  static void characteristic_free(void *data)
>> > > > > > > > > > > >  {
>> > > > > > > > > > > >         struct characteristic *chrc = data;
>> > > > > > > > > > > >
>> > > > > > > > > > > >         /* List should be empty here */
>> > > > > > > > > > > >         queue_destroy(chrc->descs, NULL);
>> > > > > > > > > > > > -       queue_destroy(chrc->notify_clients, NULL);
>> > > > > > > > > > > >
>> > > > > > > > > > > >         if (chrc->write_io) {
>> > > > > > > > > > > >                 queue_remove(chrc->service->client->ios, chrc->write_io->io);
>> > > > > > > > > > > > @@ -1663,6 +1672,8 @@ static void characteristic_free(void *data)
>> > > > > > > > > > > >                 pipe_io_destroy(chrc->notify_io);
>> > > > > > > > > > > >         }
>> > > > > > > > > > > >
>> > > > > > > > > > > > +       queue_destroy(chrc->notify_clients, remove_client);
>> > > > > > > > > > > > +
>> > > > > > > > > > > >         g_free(chrc->path);
>> > > > > > > > > > > >         free(chrc);
>> > > > > > > > > > > >  }
>> > > > > > > > > > > > @@ -1715,16 +1726,6 @@ static struct characteristic *characteristic_create(
>> > > > > > > > > > > >         return chrc;
>> > > > > > > > > > > >  }
>> > > > > > > > > > > >
>> > > > > > > > > > > > -static void remove_client(void *data)
>> > > > > > > > > > > > -{
>> > > > > > > > > > > > -       struct notify_client *ntfy_client = data;
>> > > > > > > > > > > > -       struct btd_gatt_client *client = ntfy_client->chrc->service->client;
>> > > > > > > > > > > > -
>> > > > > > > > > > > > -       queue_remove(client->all_notify_clients, ntfy_client);
>> > > > > > > > > > > > -
>> > > > > > > > > > > > -       notify_client_unref(ntfy_client);
>> > > > > > > > > > > > -}
>> > > > > > > > > > > > -
>> > > > > > > > > > > >  static void unregister_characteristic(void *data)
>> > > > > > > > > > > >  {
>> > > > > > > > > > > >         struct characteristic *chrc = data;
>> > > > > > > > > > > > @@ -1738,7 +1739,6 @@ static void unregister_characteristic(void *data)
>> > > > > > > > > > > >         if (chrc->write_op)
>> > > > > > > > > > > >                 bt_gatt_client_cancel(gatt, chrc->write_op->id);
>> > > > > > > > > > > >
>> > > > > > > > > > > > -       queue_remove_all(chrc->notify_clients, NULL, NULL, remove_client);
>> > > > > > > > > > > >         queue_remove_all(chrc->descs, NULL, NULL, unregister_descriptor);
>> > > > > > > > > > > >
>> > > > > > > > > > > >         g_dbus_unregister_interface(btd_get_dbus_connection(), chrc->path,
>> > > > > > > > > > > > --
>> > > > > > > > > > > > 2.17.2
>> > > >
>> > > > Applied.
>> > > >
>> > > > --
>> > > > Luiz Augusto von Dentz
>>
>>
>>
>> --
>> Luiz Augusto von Dentz