[Arm-dev] Issues with the 4.9.x kernel and pvrusb2 driver

Sun Feb 4 17:28:19 UTC 2018
Chris Szilagyi <chris at apex-internet.com>

[SNIP]

>>
>> Feb  3 13:11:48 bananapi kernel: pvrusb2: Unknown symbol
>> __stack_chk_guard (err 0)
>> Feb  3 13:11:48 bananapi kernel: pvrusb2: Unknown symbol
>> __stack_chk_fail (err 0)
>>
>> Using insmod directly shows this:
>> insmod: ERROR: could not insert module pvrusb2.ko: Unknown symbol in 
>> module
>>
> Are you building the whole kernel or just the module? Sounds like 
> different config, environment, etc...

Just the module.  I've been following the instructions here: 
https://wiki.centos.org/HowTos/BuildingKernelModules
But I am building on the device itself (Banana Pi).  So I'm not doing 
any cross-compiling or anything.

Could this be a problem with a different config, from the running 
kernel?  In the instructions it has be run "make oldconfig" which I 
thought was supposed to bring in the current config.  However it still 
prompts for a lot of kernel options (regarding chipsets, etc.) and I 
have tried to make a best guess at them.

>> I must still be missing something here.
>>
>> One thing I had a tough time was finding the kernel source for what 
>> is used for these ARM releases.  I googled and ended up finding: 
>> http://buildlogs-seed.centos.org/c7.1708.exp.i386/kernel/20180105174048/4.9.75-204.el7.centos.x86_64/kernel-4.9.75-204.el7.centos.src.rpm, 
>> and used that one.  I figured the src.rpm there should work so that's 
>> what I ended up using to recompile just the pvrusb2 module, not sure 
>> if that would have anything to do with the problem.
> That sounds like the right rpm, but you can also check here 
> (http://vault.centos.org/altarch/7.4.1708/experimental/Source/i386/Source/SPackages/kernel-4.9.75-204.el7.centos.src.rpm)

Thank you for the link.  Just for a test I did download this source RPM, 
and tried it but yet again I am getting the errors:

Feb  4 17:21:54 bananapi kernel: pvrusb2: loading out-of-tree module 
taints kernel.
Feb  4 17:21:54 bananapi kernel: pvrusb2: Unknown symbol 
__stack_chk_guard (err 0)
Feb  4 17:21:54 bananapi kernel: pvrusb2: Unknown symbol 
__stack_chk_fail (err 0)

Not sure why, as I thought it would be OK since the source matches the 
running kernel.

>>
>> I definitely have no problem filing a bug on bugzilla, I have a 
>> feeling they will say it's fixed in 4.14.  I'm not sure if the CentOS 
>> ARM branch will continue with the 4.9 kernel or go up to a newer one 
>> which would fix the problem entirely.  But for now if we are stuck 
>> with 4.9 I'm not sure how to proceed or if there's a way to get the 
>> patch applied for the next update.
>>
> I disagree, since both 4.4 and 4.9 are longterm, and regressions where 
> introduced in "point" releases.

OK very good, I did not know that.

Thank you again for your help.

Chris