> -----Original Message----- > From: James Bottomley [mailto:James.Bottomley@xxxxxxxxxxxxxxxxxxxxx] > Sent: Wednesday, March 04, 2015 5:05 PM > To: Praveen Murali > Cc: linux-scsi@xxxxxxxxxxxxxxx; dan.j.williams@xxxxxxxxx > Subject: Re: [libsas] Kernel Crash in smp_execute_task > > On Thu, 2015-03-05 at 00:44 +0000, Praveen Murali wrote: > > ________________________________________ > > From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> > > Sent: Wednesday, March 4, 2015 4:18 PM > > To: Praveen Murali > > Cc: linux-scsi@xxxxxxxxxxxxxxx; dan.j.williams@xxxxxxxxx > > Subject: Re: [libsas] Kernel Crash in smp_execute_task > > > > On Wed, 2015-03-04 at 23:29 +0000, Praveen Murali wrote: > > >> On second thoughts, should we even let smp commands/requests thru for > > >> sas end devices (dev->dev_type == SAS_END_DEV) ? if so, wont the > > >> following patch more sense? (also, in my last mail the kernel logs > > >> were all messed up; sorry dint realize that when I sent the mail. > > >> Trying to fix it here) > > > > >I think the bug is deeper than this: we shouldn't be trying expander > > >revalidation on non-expander devices. If the device changes from end to > > >expander via hotplug, we'll see the remove and add (via the identify > > >frame) so the device type should be correct by the time we do the > > >revalidation. > > > > >Does this fix the problem? > > > > Yes, that fixes the issue. So if my understanding is correct, what you > > are saying is we need to do something like > [the patch] > > instead of putting the exclusion in smp_execute_task; is that right? > > Right. There's more than just the SMP problem that will happen if you > try to discover an end device as an expander. The expander discovery > routines are going to try to cast to a non-existent expander device and > do all sorts of unfortunate things with what it thinks are a list of > expander phys. Effectively revalidation only needs to probe expanders > because all the other devices were fully discovered via the IDENTIFY > frames they already sent. The code is slighly obscure and it does look > like the intent was to call sas_ex_discover with any device type since > SMP to a device that doesn't have an SMP port will just fail. However, > it's safer just not to do it because half the code assumes that any > device passed into the sas_ex_.. routines can be treated as an expander. That makes sense. I tested the change and it looks good. Do you want me to send the patch? ��.n��������+%������w��{.n�����{������ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
