Re: [EXT] [RFC 0/2] Serialize timeout handling and done callback.

From: Arun Easi
Date: Mon May 31 2021 - 05:06:59 EST


On Fri, 7 May 2021, 5:31am, Daniel Wagner wrote:

> External Email
>
> ----------------------------------------------------------------------
> Hi,
>
> We got a customer report where qla2xxx was crashing only if the kernel
> was booting and ql2xextended_error_logging was set. Loading the module
> with the log option didn't trigger the crash.
>
> After starring for a long time at the crash report I figured the
> problem might be a race between the timeout handler and done callback.
> I've come up with these patches here but unfortunatly, our customer is
> not able to reproduce the problem in the lab anymore (it was caused by
> a hardware issue which got fixed). So for these patches I don't have
> any feedback.

Thanks Daniel for the report and your effort here. Agree, this needs to be
fixed.

>
> Maybe they make sense to add the driver even if I don't have prove it
> really address the mentioned bug hence this is marked as RFC.

If you do not mind, can I take this from here? This touches quite a
number of paths, and I would like to have this go through a full
regression cycle before this is merged.

That said, I had some general comments:

1. I see sp->lock was introduced, but could not locate where it was used.
2. I did not see a release of lock after a successful kref_put_lock, maybe
that piece was missed out.
3. The sp->done should be invoked only once, and I do not see if this is
taken care of.
4. sp->cmd_sp could be a SCSI IO too, where sp is not allocated
separately, so qla2x00_sp_release shall not be called for it.

Regards,
-Arun

>
> Thanks,
> Daniel
>
> Daniel Wagner (2):
> qla2xxx: Refactor asynchronous command initialization
> qla2xxx: Do not free resource to early in qla24xx_async_gpsc_sp_done()
>
> drivers/scsi/qla2xxx/qla_def.h | 5 ++
> drivers/scsi/qla2xxx/qla_gbl.h | 4 +-
> drivers/scsi/qla2xxx/qla_gs.c | 86 ++++++++++-------------------
> drivers/scsi/qla2xxx/qla_init.c | 91 +++++++++++++------------------
> drivers/scsi/qla2xxx/qla_iocb.c | 54 +++++++++++++-----
> drivers/scsi/qla2xxx/qla_mbx.c | 11 ++--
> drivers/scsi/qla2xxx/qla_mid.c | 5 +-
> drivers/scsi/qla2xxx/qla_mr.c | 7 +--
> drivers/scsi/qla2xxx/qla_target.c | 6 +-
> 9 files changed, 127 insertions(+), 142 deletions(-)
>
>