On Mon, 2021-02-01 at 22:50 +0800, lixiaokeng wrote:
>
> > >
> > > cli_add_path
> > > ->ev_add_path
> > > ->add_map_with_path
> > > ->adopt_paths
> > > ->pathinfo
> > > ->filter_property
> > > ->return PATHINFO_SKIPPED,
> > > ->pp->mpp is NULL and not be set
> > > ->return 0
> >
> > This returns 0, but add_map_with_path() has this code to check
> > whether
> > the path passed to it was actually added to the new map:
> >
> > if (adopt_paths(vecs->pathvec, mpp) ||
> > find_slot(vecs->pathvec, pp) == -1)
> > goto out; -> return NULL
> >
> > So ev_add_path() should have seen a NULL return from
> > add_map_with_path(), should not have set start_waiter, and failed.
> >
>
> I'm sorry for a big mistake in my stack. As the code is optimized,
> pathinfo
> return PATHINFO_SKIPPED after finish filter_property when I use gdb.
> It
> happens acctualy in:
> 2141 if (pp->bus == SYSFS_BUS_SCSI &&
> 2142 pp->sg_id.proto_id == SCSI_PROTOCOL_USB
> &&
> 2143 !conf->allow_usb_devices) {
> 2144 condlog(3, "%s: skip USB device %s",
> pp->dev,
> 2145 pp->tgt_node_name);
> 2146 return PATHINFO_SKIPPED;
> 2147 }
> 2148 }
>
> Stack:
> cli_add_path
> ->ev_add_path
> ->add_map_with_path
> ->adopt_paths
> ->pathinfo
> ->pp->bus == SYSFS_BUS_SCSI
> ->return PATHINFO_SKIPPED,
> ->pp->mpp is NULL and not be set
> ->return 0
> ->mpath_pr_event_handle
> ->get_be64 //pp->mpp is dereference
>
> If you think my patch is ok, I will resend it.
The same argument I made above still holds. "pp" wouldn't have been
added to mpp, and add_map_with_path() would fail and return NULL.
Also, if pathinfo() returns PATHINFO_SKIPPED for this device,
how comes that cli_add_path() called ev_add_path() for it? It should
have returned "blacklisted" instead.
Your patch would only be effective if it was possible that
add_map_with_path(vecs, pp, 1) returned an mpp != NULL, and at the same
time pp->mpp was NULL; I still don't understand how that can come to
pass.
Have you tried my patch?
Regards,
Martin
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