On 31/08/2017 10:20, Hannes Reinecke wrote:
(resending to include linux-scsi)
When removing the HBA or port there's a device_del() inversion
in sas_deform_port().
If there's only one phy it will call sas_unregister_domain_devices(),
which in turn might remove any phys and end_devices asynchronously
via the DISCE_DESTRUCT event.
But then it goes ahead and calls sas_port_delete() before the DISCE_DESTRUCT
event had a chance to run.
Consequently the port is removed before the phy, and we're getting
nasty kernel WARNING like
Hi Hannes,
Your solution looks similar to what Dan tried originally to fix this, here:
https://marc.info/?l=linux-scsi&m=143459794823595&w=2
As I recall, I was getting a NULL dereference with his.
Anyway, have you tried removing a disk from an expander? I don't see how
this is fixed-up in your patch. I quickly tested and I see the WARN.
However just removing a directly attached disk looked ok.
BTW, another colleague of mine has taken over the work we were doing on
this topic. I reviewed internally the candidate patchset yesterday, and
it still has a few issues; here's that patchset:
https://github.com/JasonYanHuawei/linux-libsas
All the best,
John
WARNING: CPU: 14 PID: 1592 at fs/sysfs/group.c:237 device_del+0x61/0x2a0()
sysfs group ffffffff81eff140 not found for kobject '6:0:0:0'
This patch moves the call to sas_port_delete() into the DISCE_DESTRUCT
handler to ensure that devices are removed in the correct order.
Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
---
drivers/scsi/libsas/sas_discover.c | 10 +++++++++-
drivers/scsi/libsas/sas_port.c | 6 ++----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index 60de662..dc8f789 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -368,6 +368,10 @@ static void sas_destruct_devices(struct work_struct *work)
sas_rphy_delete(dev->rphy);
sas_unregister_common_dev(port, dev);
}
+ if (!port->port->rphy) {
+ sas_port_delete(port->port);
+ port->port = NULL;
+ }
}
void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
@@ -401,8 +405,12 @@ void sas_unregister_domain_devices(struct asd_sas_port *port, int gone)
list_for_each_entry_safe(dev, n, &port->disco_list, disco_list_node)
sas_unregister_dev(port, dev);
+ /*
+ * Add another destruct event (or overload the existing one)
+ * to trigger port deletion.
+ */
port->port->rphy = NULL;
-
+ sas_discover_event(port, DISCE_DESTRUCT);
}
void sas_device_set_phy(struct domain_device *dev, struct sas_port *port)
diff --git a/drivers/scsi/libsas/sas_port.c b/drivers/scsi/libsas/sas_port.c
index d3c5297..7ee0c0a 100644
--- a/drivers/scsi/libsas/sas_port.c
+++ b/drivers/scsi/libsas/sas_port.c
@@ -217,11 +217,9 @@ void sas_deform_port(struct asd_sas_phy *phy, int gone)
if (dev)
dev->pathways--;
- if (port->num_phys == 1) {
+ if (port->num_phys == 1)
sas_unregister_domain_devices(port, gone);
- sas_port_delete(port->port);
- port->port = NULL;
- } else {
+ else {
sas_port_delete_phy(port->port, phy->phy);
sas_device_set_phy(dev, port->port);
}
