Re: [PATCH] Fix PR 21337 v2: segfault when re-reading symbols with remote debugging.

[Doug Gilmore <Doug dot Gilmore at imgtec dot com>]

On 04/28/17 18:41, Simon Marchi wrote:
> On 2017-04-28 19:44, Doug Gilmore wrote:
>> Hi Simon,
>>
>> After thinking about it my comment and code placement wasn't
>> particularly good.  Something along the line's of Luis's change
>> is better.
>>
>> Does Luis's comment address the question you have?
>>
>> If so, Luis: Should is it OK we incorporate your changes in the patch?
>>
>> I attached a diff for the change.
>>
>> Thanks,
>>
>> Doug
> 
> Hi Doug,
> 
> The comment certainly helps, but in the commit log I'd like to see a
> more detailed list of events that leads to the crash.
> 
> Now that I look into it again, I think I understand.  The
> objfile_pspace_info::sections array/vector is a list of obj_section
> pointers (in C++ we'd probably use an std::vector<obj_section*>).
> That list contains pointers to all the sections from all the
> objfiles sorted in order of increasing address.  They point directly
> to the sections allocated by the objfile in their obstacks (and
> accessible through objfile::sections).  So when the obstack is freed
> in reread_symbols, the sorted list contains stale pointers.  Is that
> it?
Right.
> 
> If that's what's happening, then I'm more convinced the fix is
> right.  Is this behaviour caught by a test?  If not, could you write
> one?
> ...
I'll need to take a look.  Last time I tried I it was more difficult
to expose the problem on the native build of GDB.

Thanks,

Doug