Re: [x86/entry] 2bbc68f837: ltp.ptrace08.fail

[Thomas Gleixner]

Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes:
>> On Jun 16, 2020, at 1:44 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> 
>> ïkernel test robot <rong.a.chen@xxxxxxxxx> writes:
>>> FYI, we noticed the following commit (built with gcc-9):
>>> 
>>> commit: 2bbc68f8373c0631ebf137f376fbea00e8086be7 ("x86/entry: Convert Debug exception to IDTENTRY_DB")
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>> 
>> Is the head of linux.git exposing the same problem or is this an
>> intermittent failure, which only affects bisectability?
>
> It sure looks deterministic:
>
> ptrace08.c:62: BROK: Cannot find address of kernel symbol "do_debug"

Hahahaha. But not only LTP, also LKP-tests makes assumptions:

  monitors/irq_exception_noise:[ "$exception" -eq "1" ] && export ftrace_filters='__do_page_fault do_divide_error do_overflow do_bounds do_invalid_op do_device_not_available do_double_fault do_coprocessor_segment_overrun do_invalid_TSS do_segment_not_present do_spurious_interrupt_bug do_coprocessor_error do_alignment_check do_simd_coprocessor_error do_debug do_stack_segment do_general_protection'

stable-api-nonsense.rst comes to my mind.

Thanks,

        tglx