RE: [PATCH v2 2/2] gdb: raise and handle NOT_AVAILABLE_ERROR when accessing frame PC

["Aktemur, Tankut Baris" <tankut.baris.aktemur@intel.com>]

On Wednesday, March 23, 2022 2:35 PM, Bruno Larsen wrote:
> On 3/23/22 09:55, Aktemur, Tankut Baris wrote:
> > On Wednesday, March 16, 2022 6:27 PM, Bruno Larsen wrote:
> >>> Finally, together with its predecessor, this patch also fixes PR gdb/26877.
> >>
> >> While I think this is a good idea, it doesn't seem to fix the root cause of the bug you
> >> mentioned. It does stop the crash that the bug reports, but I would say the actual issue
> is
> >> that GDB is not noticing that the second inferior is also finished. My 2 cents, for what
> >> they're worth.
> >
> > The root cause was an unhandled error in a destructor.  The 2-inferior setup was
> > just one way to expose it.  From https://sourceware.org/bugzilla/show_bug.cgi?id=26877#c0:
> >
> > 	The problem is at:
> >
> > 	#20 0x00005555561128b9 in program_space::~program_space (this=0x55555830a070,
> __in_chrg=<optimized out>) at gdb/progspace.c:153
> >
> > 	While inside a destructor, GDB wanted to access the frame information
> > 	of Inferior 2 in a series of calls.  But because the process is dead, its
> > 	registers cannot be read.  This raises an error inside a destructor, leading
> > 	to termination of GDB.
> >
> >  From that perspective, I think the root cause is fixed.
> >
> 
> It is the root cause of the crash, but GDB is still not aware that the second inferior has
> finished, which is still a problem, IMHO.

I agree that it's a problem.  The essence of the problem is that
the other inferior has terminated but this has not been shown to
the user, yet.  The event is pending.  I believe it can be the
topic of another fix.  I'm afraid it's a wider problem outside the
scope of what I submitted.

Regards
-Baris


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