Re: [PATCH] gdb/testsuite: make gdb.dwarf2/dw2-empty-inline-ranges.exp work when ASLR can't be disabled

[Simon Marchi <simark@simark.ca>]

On 2026-02-06 09:14, Andrew Burgess wrote:
> Simon Marchi <simon.marchi@efficios.com> writes:
> 
>> A colleague that goes by the name "Luis Machado" reported a failure when
>> running gdb.dwarf2/dw2-empty-inline-ranges.exp.  After investigation, we
>> found that the conditions for the test to fail are:
>>
>>  - running in an environment where GDB can't disable address space
>>    randomization (such as in a container where that capability is
>>    removed)
>>
>>  - a toolchain generating position-independent executables
>>
>> The test does a first run to grab the addresses of a few labels defined
>> in the source file.  It then crafts the DWARF using these addresses.
>> And then it does a second run for the actual test stuff.
>>
>> When the executable is PIE and ASLR is active, then the addresses in
>> both runs don't agree, which the test doesn't expect.
>>
>> It is possible to emulate the failure by inserting some:
>>
>>     gdb_test_no_output "set disable-randomization off"
>>
>> after both "prepare_for_testing" calls.  The (first) failure then
>> manifests as:
>>
>>     FAIL: gdb.dwarf2/dw2-empty-inline-ranges.exp: dwarf_version=4: empty_loc=start: entry_pc_type=empty: stopped at entry-pc
>>
>> This test compares the expected stop PC "entry_pc" with the actual stop
>> PC "pc".  In my example run, they were indeed different:
>>
>>     pc       = 0x5603ec67a159
>>     entry_pc = 0x55baba6a9159
>>
>> The simplest way to fix this, which this patch implements, is to use
>> "nopie" when building the binaries.  I don't think this affects the
>> effectiveness of the test.
>>
>> Also, in the first run, it is longer necessary to run the inferior
>> before grabbing the addresses, they are going to be the same with a
>> non-PIE executable.  So remove that.
> 
> Thanks for fixing this.  LGTM.
> 
> Approved-By: Andrew Burgess <aburgess@redhat.com>
> 
> 
> Thanks,
> Andrew
> 

Thanks, pushed.  I actually added a small comment in the test file to
explain why we use nopie.

Simon