[ 14/27] SCSI: libsas: fix handling vacant phy in sas_set_ex_phy()

From: Greg Kroah-Hartman
Date: Sun Apr 14 2013 - 22:43:58 EST

3.8-stable review patch. If anyone has any objections, please let me know.


From: Lukasz Dorau <lukasz.dorau@xxxxxxxxx>

commit d4a2618fa77b5e58ec15342972bd3505a1c3f551 upstream.

If a result of the SMP discover function is PHY VACANT,
the content of discover response structure (dr) is not valid.
It sometimes happens that dr->attached_sas_addr can contain
even SAS address of other phy. In such case an invalid phy
is created, what causes NULL pointer dereference during
destruction of expander's phys.

So if a result of SMP function is PHY VACANT, the content of discover
response structure (dr) must not be copied to phy structure.

This patch fixes the following bug:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
IP: [<ffffffff811c9002>] sysfs_find_dirent+0x12/0x90
Call Trace:
[<ffffffff811c95f5>] sysfs_get_dirent+0x35/0x80
[<ffffffff811cb55e>] sysfs_unmerge_group+0x1e/0xb0
[<ffffffff813329f4>] dpm_sysfs_remove+0x24/0x90
[<ffffffff8132b0f4>] device_del+0x44/0x1d0
[<ffffffffa016fc59>] sas_rphy_delete+0x9/0x20 [scsi_transport_sas]
[<ffffffffa01a16f6>] sas_destruct_devices+0xe6/0x110 [libsas]
[<ffffffff8107ac7c>] process_one_work+0x16c/0x350
[<ffffffff8107d84a>] worker_thread+0x17a/0x410
[<ffffffff81081b76>] kthread+0x96/0xa0
[<ffffffff81464944>] kernel_thread_helper+0x4/0x10

Signed-off-by: Lukasz Dorau <lukasz.dorau@xxxxxxxxx>
Signed-off-by: Pawel Baldysiak <pawel.baldysiak@xxxxxxxxx>
Reviewed-by: Maciej Patelczyk <maciej.patelczyk@xxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/scsi/libsas/sas_expander.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -235,6 +235,17 @@ static void sas_set_ex_phy(struct domain
linkrate = phy->linkrate;
memcpy(sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);

+ /* Handle vacant phy - rest of dr data is not valid so skip it */
+ if (phy->phy_state == PHY_VACANT) {
+ memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
+ phy->attached_dev_type = NO_DEVICE;
+ if (!test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state)) {
+ phy->phy_id = phy_id;
+ goto skip;
+ } else
+ goto out;
+ }
phy->attached_dev_type = to_dev_type(dr);
if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state))
goto out;
@@ -272,6 +283,7 @@ static void sas_set_ex_phy(struct domain
phy->phy->maximum_linkrate = dr->pmax_linkrate;
phy->phy->negotiated_linkrate = phy->linkrate;

+ skip:
if (new_phy)
if (sas_phy_add(phy->phy)) {

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