Re: Fw: [Bug 214619] New: Aquantia / Atlantic driver not loading post 5.14.RC7

Hello community,

            Bug ID: 214619
           Summary: Aquantia / Atlantic driver not loading post 5.14.RC7
           Product: Networking
           Version: 2.5
    Kernel Version: 514.rc7
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: Other
          Assignee: stephen@networkplumber.org
          Reporter: Miles.Rumppe@gmail.com
        Regression: No

https://bugzilla.kernel.org/show_bug.cgi?id=214619

Quite a strange issue, we are looking for advice/assistance.

After looking into disassembly, I see the failure is AFTER the end of the function:

    272d:       b8 01 00 00 00          mov    $0x1,%eax
    2732:       d3 e0                   shl    %cl,%eax
    2734:       41 09 85 f8 05 00 00    or     %eax,0x5f8(%r13)
    273b:       eb 84                   jmp    26c1 <aq_nic_start+0x301>

quoted

 273d:       0f 0b                   ud2    

    273f:       90                      nop

On undefined instruction.

We had similar report in past from another user, but were unable to find out how execution could reach that point.

I suspect this is something related to compiler optimization or some other coincidence.

We also were not successful in trying to bisect this driver specific changes. Looks like some side kernel change could have triggered that.

Any clue?

Regards,
  Igor