I'm trying to debug a nonresponsive device when using Linux 5.4-rt compared to 4.19-rt. However, after loading the symbols (add-symbol-file vmlinux), I get this error message:
WARNING(ROS60): Could not enable OS support as the OS does not appear to be initialized. This might be caused by a mismatch between the loaded symbols and the code on the target or because the OS is not up and running. Enabling OS support will be re-attempted when the target next stops.
Note that kernel debugging works fine with Linux 4.19-rt. I'm using Arm Development Studio 2020.0 (Intel FPGA Version) and debugging a Cyclone V SoC using an Altera USB-Blaster II, if that's of any interest.
Can anyone tell me what's the limit here? Why does it work for 4.19, but not for 5.4?
As a quick sanity check - has the new kernel been built for debug:
Does the debugger display symbols correctly, just not the OS awareness?
Yes, the debugger displays the symbols and call stack correctly. The kernel config should be ok. In fact, it's the same config for both versions where 4.19 works but 5.4 doesn't. It's really only the OS awareness that isn't working. And with that, I also cannot debug kernel modules.
I've had the same problem with DS-5 from 2014, where 4.19 did not (yet?) work and I got the same error message.
Hi again Simon,
We are investigating internally at Arm. In the meantime, would it be possible to let me know the output of 'uname -r' from your target?
It may also be useful if we can access your vmlinux file - would it be possible to share this? For security, it is probably best to create an 'official' support case from the support menu above (please reference this community thread so we can track appropriately), and transfer the file that way.
Thanks for the reply. I've opened CAS-178556-H2W9R3 for this and attached my vmlinux, as requested.
Just for the record, here's my output of "uname -a" (which is also in the support case):Linux panosdevice 5.4-rt-pf-socfpga-cyclone5 #1 SMP PREEMPT_RT Fri Sep 11 13:33:01 CEST 2020 armv7l GNU/Linux
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