Bluetooth 6lowpan ping6 slab corruption

Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

Hi,

I have enabled 6lowpan and bluetooth 6lowpan in the kernel configuration on two systems. Both these systems are running linux and one act as a master and another act as a slave.
I am facing a bug while in a bluetooth 6lowpan connection. This happens during a ping6. The kernel version that I am using is 4.1.27 with BlueZ 5.40 on a x86_64 architecture. The kernel reports regarding slab corruption.

The steps that I have performed are as follows:
Slave device:
$ modprobe 6lowpan
$ modprobe Bluetooth_6lowpan
$ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
$ hciconfig hci0 leadv 

Master device:
$ modprobe 6lowpan
$ modprobe bluetooth_6lowpan
$ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
$ hcitool lescan << to obtain slave BT ADDR
$ echo "connect <remote_BT_MAC> 1" > /sys/kernel/debug/bluetooth/6lowpan_control
$ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device
$ ping6 -I bt0 <IPV6_ADDR>     <<<<------ The console message starts to appear here during ping6

The output of the console message:

[  794.985623] Slab corruption (Tainted: G     U         ): skbuff_head_cache start=ffff8801f568f700, len=232
[  795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  ....kkkkkkkkkkkk
[  795.029380] Prev obj: start=ffff8801f568f600, len=232
[  795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[  795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[  795.076752] Next obj: start=ffff8801f568f800, len=232
[  795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
[  795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk

The 6lowpan connection between the two devices is connected.
I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that.
Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so.
This also persists when ping6 is done from the slave to the master. 

Do you know what could possibly cause this issue?

Please let me know if you require further information.

Thank you.

Best regards,
Joshua

Re: Bluetooth 6lowpan ping6 slab corruption

[Alexander Aring]

On 12/16/2016 07:46 AM, Wong, Joshua Weng Onn wrote:
> Hi,
> 
> I have enabled 6lowpan and bluetooth 6lowpan in the kernel configuration on two systems. Both these systems are running linux and one act as a master and another act as a slave.
> I am facing a bug while in a bluetooth 6lowpan connection. This happens during a ping6. The kernel version that I am using is 4.1.27 with BlueZ 5.40 on a x86_64 architecture. The kernel reports regarding slab corruption.
> 
> The steps that I have performed are as follows:
> Slave device:
> $ modprobe 6lowpan
> $ modprobe Bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hciconfig hci0 leadv 
> 
> Master device:
> $ modprobe 6lowpan
> $ modprobe bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hcitool lescan << to obtain slave BT ADDR
> $ echo "connect <remote_BT_MAC> 1" > /sys/kernel/debug/bluetooth/6lowpan_control
> $ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device
> $ ping6 -I bt0 <IPV6_ADDR>     <<<<------ The console message starts to appear here during ping6
> 
> The output of the console message:
> 
> [  794.985623] Slab corruption (Tainted: G     U         ): skbuff_head_cache start=ffff8801f568f700, len=232
> [  795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  ....kkkkkkkkkkkk
> [  795.029380] Prev obj: start=ffff8801f568f600, len=232
> [  795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.076752] Next obj: start=ffff8801f568f800, len=232
> [  795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> [  795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> 
> The 6lowpan connection between the two devices is connected.
> I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that.
> Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so.
> This also persists when ping6 is done from the slave to the master. 
> 
> Do you know what could possibly cause this issue?
> 
> Please let me know if you require further information.
> 

In short:

BTLE 6LoWPAN is broken. Patch-Series which needs some love to fix some
issues (mostly races/L2 address handling with L3 stuff, use ndisc stuff,
still exists open question which L2 address should be used) exists at
[0].

Maybe YOU want to bring it mainline -> I have no time currently to do that.
Of maybe you can test it and tell me your expierence. :-)

If you want still to use the current code, I recommend to disable SMP...
but races still exists. Also update the kernel version to a recent one.

- Alex

[0] http://www.spinics.net/lists/linux-wpan/msg04124.html

Re: Bluetooth 6lowpan ping6 slab corruption

[Alexander Aring]

On 12/16/2016 07:46 AM, Wong, Joshua Weng Onn wrote:
> Hi,
> 
> I have enabled 6lowpan and bluetooth 6lowpan in the kernel configuration on two systems. Both these systems are running linux and one act as a master and another act as a slave.
> I am facing a bug while in a bluetooth 6lowpan connection. This happens during a ping6. The kernel version that I am using is 4.1.27 with BlueZ 5.40 on a x86_64 architecture. The kernel reports regarding slab corruption.
> 
> The steps that I have performed are as follows:
> Slave device:
> $ modprobe 6lowpan
> $ modprobe Bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hciconfig hci0 leadv 
> 
> Master device:
> $ modprobe 6lowpan
> $ modprobe bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hcitool lescan << to obtain slave BT ADDR
> $ echo "connect <remote_BT_MAC> 1" > /sys/kernel/debug/bluetooth/6lowpan_control
> $ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device
> $ ping6 -I bt0 <IPV6_ADDR>     <<<<------ The console message starts to appear here during ping6
> 
> The output of the console message:
> 
> [  794.985623] Slab corruption (Tainted: G     U         ): skbuff_head_cache start=ffff8801f568f700, len=232
> [  795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  ....kkkkkkkkkkkk
> [  795.029380] Prev obj: start=ffff8801f568f600, len=232
> [  795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.076752] Next obj: start=ffff8801f568f800, len=232
> [  795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> [  795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> 
> The 6lowpan connection between the two devices is connected.
> I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that.
> Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so.
> This also persists when ping6 is done from the slave to the master. 
> 
> Do you know what could possibly cause this issue?
> 
> Please let me know if you require further information.
> 

In short:

BTLE 6LoWPAN is broken. Patch-Series which needs some love to fix some
issues (mostly races/L2 address handling with L3 stuff, use ndisc stuff,
still exists open question which L2 address should be used) exists at
[0].

Maybe YOU want to bring it mainline -> I have no time currently to do that.
Of maybe you can test it and tell me your expierence. :-)

If you want still to use the current code, I recommend to disable SMP...
but races still exists. Also update the kernel version to a recent one.

- Alex

[0] http://www.spinics.net/lists/linux-wpan/msg04124.html

RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

On 12/16/2016 07:46 AM, Wong, Joshua Weng Onn wrote:
> Hi,
> 
> I have enabled 6lowpan and bluetooth 6lowpan in the kernel configuration on two systems. Both these systems are running linux and one act as a master and another act as a slave.
> I am facing a bug while in a bluetooth 6lowpan connection. This happens during a ping6. The kernel version that I am using is 4.1.27 with BlueZ 5.40 on a x86_64 architecture. The kernel reports regarding slab corruption.
> 
> The steps that I have performed are as follows:
> Slave device:
> $ modprobe 6lowpan
> $ modprobe Bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hciconfig hci0 leadv
> 
> Master device:
> $ modprobe 6lowpan
> $ modprobe bluetooth_6lowpan
> $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable
> $ hcitool lescan << to obtain slave BT ADDR $ echo "connect 
> <remote_BT_MAC> 1" > /sys/kernel/debug/bluetooth/6lowpan_control
> $ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device
> $ ping6 -I bt0 <IPV6_ADDR>     <<<<------ The console message starts to appear here during ping6
> 
> The output of the console message:
> 
> [  794.985623] Slab corruption (Tainted: G     U         ): skbuff_head_cache start=ffff8801f568f700, len=232
> [  795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  
> ....kkkkkkkkkkkk [  795.029380] Prev obj: start=ffff8801f568f600, 
> len=232 [  795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.076752] Next obj: start=ffff8801f568f800, len=232 [  
> 795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  
> kkkkkkkkkkkkkkkk [  795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 
> 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> 
> The 6lowpan connection between the two devices is connected.
> I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that.
> Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so.
> This also persists when ping6 is done from the slave to the master. 
> 
> Do you know what could possibly cause this issue?
> 
> Please let me know if you require further information.
> 

In short:

BTLE 6LoWPAN is broken. Patch-Series which needs some love to fix some issues (mostly races/L2 address handling with L3 stuff, use ndisc stuff, still exists open question which L2 address should be used) exists at [0].

Maybe YOU want to bring it mainline -> I have no time currently to do that.
Of maybe you can test it and tell me your expierence. :-)

If you want still to use the current code, I recommend to disable SMP...
but races still exists. Also update the kernel version to a recent one.

- Alex

[0] http://www.spinics.net/lists/linux-wpan/msg04124.html

Thank you for informing me about this. Sorry as I was not aware of the newer patches that you submitted to mainline.
At the moment I am not able to upgrade the kernel to a recent version as the other teams in my department are using kernel version 4.1.27 and I have to follow it strictly.

I just got an idea. Perhaps what I can do is backport the patches and apply them to this version of the kernel. I am not sure if it will work entirely. I'll discuss this with my lead first if he wants me to do this and let you know if I am pursuing this.

Best regards,
Joshua
 
--
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Re: Bluetooth 6lowpan ping6 slab corruption

[Alexander Aring]

Hi,

On 12/16/2016 09:18 AM, Wong, Joshua Weng Onn wrote:
...
> 
> Thank you for informing me about this. Sorry as I was not aware of the newer patches that you submitted to mainline.
> At the moment I am not able to upgrade the kernel to a recent version as the other teams in my department are using kernel version 4.1.27 and I have to follow it strictly.
> 
> I just got an idea. Perhaps what I can do is backport the patches and apply them to this version of the kernel. I am not sure if it will work entirely. I'll discuss this with my lead first if he wants me to do this and let you know if I am pursuing this.
> 

You can backport it, yes... but please _please_ don't do it... bring it
mainline and then backport it.

Tell that your lead as suggestion from me.

It makes no sense that you backporting it only for you. This thing need
to be fixed upstream...

In my opinion, all people who backporting it will do work for nothing...
The next guy/girl which wants to try that out runs again into such
issues.

These patches was sending to bluetooth-next, now I am busy with other
things and can work on it at end of April maybe... and I think only in
my free-time. This patch-series just needs a little cleanup and send as
PATCH...

- Alex

Re: Bluetooth 6lowpan ping6 slab corruption

[Luiz Augusto von Dentz]

Hi Joshua,

On Fri, Dec 16, 2016 at 8:46 AM, Wong, Joshua Weng Onn
<joshua.weng.onn.wong@intel.com> wrote:
> $ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device

This is not right, the address of bt0 is in fact the local address not
the remote address, not sure if that could cause the problems bellow
though.

> $ ping6 -I bt0 <IPV6_ADDR>     <<<<------ The console message starts to appear here during ping6
>
> The output of the console message:
>
> [  794.985623] Slab corruption (Tainted: G     U         ): skbuff_head_cache start=ffff8801f568f700, len=232
> [  795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  ....kkkkkkkkkkkk
> [  795.029380] Prev obj: start=ffff8801f568f600, len=232
> [  795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> [  795.076752] Next obj: start=ffff8801f568f800, len=232
> [  795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
> [  795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
>
> The 6lowpan connection between the two devices is connected.
> I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that.
> Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so.
> This also persists when ping6 is done from the slave to the master.
>
> Do you know what could possibly cause this issue?
>
> Please let me know if you require further information.
>
> Thank you.
>
> Best regards,
> Joshua
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Luiz Augusto von Dentz

RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

Hi Alex,

> Hi,
> 
> On 12/16/2016 09:18 AM, Wong, Joshua Weng Onn wrote:
> ...
> >
> > Thank you for informing me about this. Sorry as I was not aware of the newer
> patches that you submitted to mainline.
> > At the moment I am not able to upgrade the kernel to a recent version as the
> other teams in my department are using kernel version 4.1.27 and I have to
> follow it strictly.
> >
> > I just got an idea. Perhaps what I can do is backport the patches and apply
> them to this version of the kernel. I am not sure if it will work entirely. I'll discuss
> this with my lead first if he wants me to do this and let you know if I am pursuing
> this.
> >
> 
> You can backport it, yes... but please _please_ don't do it... bring it mainline and
> then backport it.
> 
> Tell that your lead as suggestion from me.
> 
> It makes no sense that you backporting it only for you. This thing need to be
> fixed upstream...
> 
> In my opinion, all people who backporting it will do work for nothing...
> The next guy/girl which wants to try that out runs again into such issues.
> 
> These patches was sending to bluetooth-next, now I am busy with other things
> and can work on it at end of April maybe... and I think only in my free-time. This
> patch-series just needs a little cleanup and send as PATCH...
> 
> - Alex

I've finally just learned how to add inline '>' characters to the previous email. Had to make some changes in my email settings.

Thank you very much for your reply.
Ok noted on that. My most sincere apologies as I am quite new to this and I am still trying to understand how open source works. Didn't realize that it will cause repetitive work for others.

I will discuss this with my technical lead and update you along the way.

Thank you.

Best regards,
Joshua

RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

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RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

> From: JANARDHANACHARI KELLA [mailto:eni.chari@gmail.com] 
> Sent: Monday, December 19, 2016 2:34 PM
> To: Alexander Aring <aar@pengutronix.de>; Wong, Joshua Weng Onn <joshua.weng.onn.wong@intel.com>
> Cc: linux-wpan@vger.kernel.org
> Subject: Re: Bluetooth 6lowpan ping6 slab corruption
>
> hi sir,
> why am i not able to send any message to linux-wpan@@vger.kernel.org mailing list..
>
>
> with Regards
> Janardhanachari Kella
>
Hi Janard,

You can only send Plain Text to the mailing list. You will first need to turn off HTML encodings. Probably that was why your email was rejected.
Also, you need to perform bottom posting and not top posting i.e. send reply at the bottom of an email.
Third, you need to prepend the '>' character of the previous original message

-Joshua-

> On Mon, Dec 19, 2016 at 5:57 AM, Wong, Joshua Weng Onn <joshua.weng.onn.wong@intel.com> wrote:
> Hi Alex,

> Hi,
>
> On 12/16/2016 09:18 AM, Wong, Joshua Weng Onn wrote:
> ...
> >
> > Thank you for informing me about this. Sorry as I was not aware of the newer
> patches that you submitted to mainline.
> > At the moment I am not able to upgrade the kernel to a recent version as the
> other teams in my department are using kernel version 4.1.27 and I have to
> follow it strictly.
> >
> > I just got an idea. Perhaps what I can do is backport the patches and apply
> them to this version of the kernel. I am not sure if it will work entirely. I'll discuss
> this with my lead first if he wants me to do this and let you know if I am pursuing
> this.
> >
>
> You can backport it, yes... but please _please_ don't do it... bring it mainline and
> then backport it.
>
> Tell that your lead as suggestion from me.
>
> It makes no sense that you backporting it only for you. This thing need to be
> fixed upstream...
>
> In my opinion, all people who backporting it will do work for nothing...
> The next guy/girl which wants to try that out runs again into such issues.
>
> These patches was sending to bluetooth-next, now I am busy with other things
> and can work on it at end of April maybe... and I think only in my free-time. This
> patch-series just needs a little cleanup and send as PATCH...
>
> - Alex

I've finally just learned how to add inline '>' characters to the previous email. Had to make some changes in my email settings.

Thank you very much for your reply.
Ok noted on that. My most sincere apologies as I am quite new to this and I am still trying to understand how open source works. Didn't realize that it will cause repetitive work for others.

I will discuss this with my technical lead and update you along the way.

Thank you.

Best regards,
Joshua
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-- 
Sincerely Your's

Janardhanachari Kella
Contact:+91-9908469599
E-mail: eni.chari@gmail.com

Re: Bluetooth 6lowpan ping6 slab corruption

[Alexander Aring]

Hi,

On 12/19/2016 07:38 AM, Wong, Joshua Weng Onn wrote:
>> From: JANARDHANACHARI KELLA [mailto:eni.chari@gmail.com] 
>> Sent: Monday, December 19, 2016 2:34 PM
>> To: Alexander Aring <aar@pengutronix.de>; Wong, Joshua Weng Onn <joshua.weng.onn.wong@intel.com>
>> Cc: linux-wpan@vger.kernel.org
>> Subject: Re: Bluetooth 6lowpan ping6 slab corruption
>>
>> hi sir,
>> why am i not able to send any message to linux-wpan@@vger.kernel.org mailing list..
>>
>>
>> with Regards
>> Janardhanachari Kella
>>
> Hi Janard,
> 
> You can only send Plain Text to the mailing list. You will first need to turn off HTML encodings. Probably that was why your email was rejected.
> Also, you need to perform bottom posting and not top posting i.e. send reply at the bottom of an email.
> Third, you need to prepend the '>' character of the previous original message
> 

again and for all:

check http://vger.kernel.org/majordomo-info.html

Important part is "Taboo things".

- Alex

RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

Hi Alex,


> Hi Alex,
> 
> > Hi,
> >
> > On 12/16/2016 09:18 AM, Wong, Joshua Weng Onn wrote:
> > ...
> > >
> > > Thank you for informing me about this. Sorry as I was not aware of
> > > the newer
> > patches that you submitted to mainline.
> > > At the moment I am not able to upgrade the kernel to a recent
> > > version as the
> > other teams in my department are using kernel version 4.1.27 and I
> > have to follow it strictly.
> > >
> > > I just got an idea. Perhaps what I can do is backport the patches
> > > and apply
> > them to this version of the kernel. I am not sure if it will work
> > entirely. I'll discuss this with my lead first if he wants me to do
> > this and let you know if I am pursuing this.
> > >
> >
> > You can backport it, yes... but please _please_ don't do it... bring
> > it mainline and then backport it.
> >
> > Tell that your lead as suggestion from me.
> >
> > It makes no sense that you backporting it only for you. This thing
> > need to be fixed upstream...
> >
> > In my opinion, all people who backporting it will do work for nothing...
> > The next guy/girl which wants to try that out runs again into such issues.
> >
> > These patches was sending to bluetooth-next, now I am busy with other
> > things and can work on it at end of April maybe... and I think only in
> > my free-time. This patch-series just needs a little cleanup and send as PATCH...
> >
> > - Alex
> 
> I've finally just learned how to add inline '>' characters to the previous email.
> Had to make some changes in my email settings.
> 
> Thank you very much for your reply.
> Ok noted on that. My most sincere apologies as I am quite new to this and I am
> still trying to understand how open source works. Didn't realize that it will cause
> repetitive work for others.
> 
> I will discuss this with my technical lead and update you along the way.
> 
> Thank you.
> 
> Best regards,
> Joshua

I have discussed this with my technical lead and that he mentioned that we will not be able to pursue to bring it to Linux mainline and also not able to backport the drivers due to resource limitation. We have pending tasks/projects that are upcoming.

Just curious, can we know the estimated timeline that it will take for an inexperienced person in Linux kernel development to complete this task?

Thank you.

Best regards,
Joshua

Re: Bluetooth 6lowpan ping6 slab corruption

[Alexander Aring]

Hi,

sorry for the delay...

On 12/22/2016 12:38 AM, Wong, Joshua Weng Onn wrote:
...
> 
> I have discussed this with my technical lead and that he mentioned that we will not be able to pursue to bring it to Linux mainline and also not able to backport the drivers due to resource limitation. We have pending tasks/projects that are upcoming.
> 
ok.

> Just curious, can we know the estimated timeline that it will take for an inexperienced person in Linux kernel development to complete this task?
> 

it would take so long until everything is fine and every reviewer has no
comments on it what it could be made better...

But one issue at my patch series is that bluetooth L2CAP code has not
asynchronous Transmit function, which is not that what it's expected by
netdev xmit callback...

So I queued it into a workqueue -> some people would say it's a bug,
some people would say "it's works for now".

I think it's also very difficult to add such behaviour because
l2cap_chan mutex need to be replaced by some different fast locking
mechanism - if linux-bluetooth really want such behaviour...

Anyway, queueing into a workqueue is "okay" for me, because the way to
do it right would be complicated. :-/

Also there exists still the question about which L2 address should be
really be used and when we need to set it.

- Alex

RE: Bluetooth 6lowpan ping6 slab corruption

[Wong, Joshua Weng Onn]

> Hi,
> 
> sorry for the delay...
> 
> On 12/22/2016 12:38 AM, Wong, Joshua Weng Onn wrote:
> ...
> >
> > I have discussed this with my technical lead and that he mentioned that we will
> not be able to pursue to bring it to Linux mainline and also not able to backport
> the drivers due to resource limitation. We have pending tasks/projects that are
> upcoming.
> >
> ok.
> 
> > Just curious, can we know the estimated timeline that it will take for an
> inexperienced person in Linux kernel development to complete this task?
> >
> 
> it would take so long until everything is fine and every reviewer has no
> comments on it what it could be made better...
> 
> But one issue at my patch series is that bluetooth L2CAP code has not
> asynchronous Transmit function, which is not that what it's expected by netdev
> xmit callback...
> 
> So I queued it into a workqueue -> some people would say it's a bug, some
> people would say "it's works for now".
> 
> I think it's also very difficult to add such behaviour because l2cap_chan mutex
> need to be replaced by some different fast locking mechanism - if linux-
> bluetooth really want such behaviour...
> 
> Anyway, queueing into a workqueue is "okay" for me, because the way to do it
> right would be complicated. :-/
> 
> Also there exists still the question about which L2 address should be really be
> used and when we need to set it.
> 
> - Alex

Hi Alex,

Thank you for your reply. I will forward this to my technical lead so that he is informed of this.

Best regards,
Joshua