Re: [rfa/gdbserver] Fix crash in thread_db_get_tls_address

[Doug Evans <dje at google dot com>]

On Thu, Jan 22, 2009 at 7:05 AM, Ulrich Weigand <uweigand@de.ibm.com> wrote:
> Doug Evans wrote:
>
>> Hi.  I've run into similar situations with the thread layer not yet
>> initialized.  One aspect of this patch is a bit confusing.  Maybe a
>> comment is warranted.
>>
>> Returning -1 will cause server.c:handle_query to mark the packet as
>> unknown which will in turn cause remote.c:packet_ok to mark the packet
>> as disabled (on the gdb side).  How does the packet get re-enabled if
>> the thread layer is later initialized?
>
> You're right -- I missed that.  I guess we need to report an error
> instead of marking the packet as unknown.
>
> The following patch is changed to use TD_ERR ("generic error" seems to
> be the best response -- I don't see a more specific code that would be
> appropriate here).
>
> Retested on powerpc64-linux (64-bit / 32-bit) with local gdbserver.

I don't know if there's a better value to use here either.  Maybe
TD_TLSDEFER, but I'm just guessing (and I don't know how portable it
is).

>
> Bye,
> Ulrich
>
>
> ChangeLog:
>
>        * thread-db.c (thread_db_get_tls_address): Do not crash if
>        called when thread layer is not yet initialized.
>
>
> Index: src/gdb/gdbserver/thread-db.c
> ===================================================================
> --- src.orig/gdb/gdbserver/thread-db.c
> +++ src/gdb/gdbserver/thread-db.c
> @@ -388,6 +388,10 @@ thread_db_get_tls_address (struct thread
>   td_err_e err;
>   struct process_info *process;
>
> +  /* If the thread layer is not (yet) initialized, fail.  */
> +  if (!all_symbols_looked_up)
> +    return TD_ERR;
> +
>   process = get_thread_process (thread);
>   if (!process->thread_known)
>     find_one_thread (process->lwpid);
>
>
> --
>  Dr. Ulrich Weigand
>  GNU Toolchain for Linux on System z and Cell BE
>  Ulrich.Weigand@de.ibm.com
>