[Stgt-devel] segfault in the ssc code ...

Richard Sharpe realrichardsharpe
Sat Jul 26 03:23:16 CEST 2008

On Fri, Jul 25, 2008 at 5:12 PM, Richard Sharpe
<realrichardsharpe at gmail.com> wrote:
> On Fri, Jul 25, 2008 at 2:31 PM, Richard Sharpe
> <realrichardsharpe at gmail.com> wrote:
>> Hi,
>> There is a segfault in the ssc code when using it with the smc code
>> because it seems that bs_ssc_open is not called when you move a tape
>> into the transfer unit.
>> I am currently looking at what the best approach is here, but it seems
>> the smc.c code calls target.c:dtd_load_unload which calls
>> backed_file_open, but it seems that nothing calls bs_thread_open, so
>> later when a bs_thread_cmd_submit is called, the pending_list is not
>> initialized and we segfault.
>> I am currently wading through the code to see if I can figure out
>> where this should be set up. It would seem like it should be done when
>> we move a unit into the transfer station in the smc.c code but I am
>> not sure.
> I was wondering if this change would do the trick:
> In usr/smc.c, change set_slot_full to take a target structure as well
> as the other args, and from that call tgt_set_device_path_update,
> which will also call the correct things ...
> and in set_slot_empty, also call tdt_set_device_path_update ...
> That seems like the smallest number of changes to fix the problem I am
> seeing ...
> Does anyone have any comments on the damage this might do, though?

OK, so I made those changes, and added a mode page that bs_rdwr.c
needed, and then tar was able to write to the virtual tape I moved
into the data transfer device ...

Just like magic ...

Got to clean up the changes and then send around a patch.

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