Re: [PATCH] gdb questions: fallback on maps still relevant today ?

[Matthieu Longo <matthieu.longo@arm.com>]

On 01/07/2026 13:33, Luis wrote:
> Hi,
> 
> On 01/07/2026 13:17, Matthieu Longo wrote:
>> I am wondering whether the fallback on maps when reading smaps is still
>> relevant nowadays. /proc/$PID/smaps has been around since 2005. I doubt
>> that anyone using an older Linux kernel version out there would use the
>> latest version of GDB.
>> I propose to remove this fallback logic in linux_find_memory_regions_full.
> 
> That´d be fine by me. We might want to do the deprecation dance and then drop from a future release.
> 

What do you mean by "deprecation dance" ?
What would the steps be to get rid of this fallback ?
>> Additionnally, reading from smaps file is tested against NULL. Why ?
>> Is there such a valid case where the result of target_fileio_read_stralloc()
>> could be null, and at the same time, GDB is attached to a process, local
>> or remote via gdbserver, or while reading a coredump ?
>> In my understanding, all those cases ensures that the smaps file is always
>> present and so, I propose to replace this check with a gdb_assert instead.
> 
> There are error cases. And this file isn´t something static on disk but rather a dynamically-created
> file on request. Due to that, bad things can happen and a read may fail.
> 
> We don´t want to assert on a temporary hiccup as it will completely kill gdb during a debug session.
> If this error ever happens the user gets a warning or error message and can take action. That isn´t
> the case with assertions.
> 

Ok

>>
>> Why do I care about the above ?
>> I would like to wrap the reading and parsing code in a class to avoid
>> the duplication of all the boiler plates in different places.
> 
> Can´t you accomplish that already regardless of whether reading smaps fails or not?
>

I can. I was wondering whether it was possible to tidy things up before adding wrappers.

Matthieu