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authorSteffen Maier <maier@linux.vnet.ibm.com>2011-11-18 20:00:40 +0100
committerJames Bottomley <JBottomley@Parallels.com>2011-12-14 15:40:43 +0400
commit44f747fff6e9f027a4866c1a6864e26ae7c510c8 (patch)
treebbaf28b480018835fb61db1dd13ce8bd4d4e8b97 /drivers/s390
parent7e1e7ead88dff75b11b86ee0d5232c4591be1326 (diff)
[SCSI] zfcp: return early from slave_destroy if slave_alloc returned early
zfcp_scsi_slave_destroy erroneously always tried to finish its task even if the corresponding previous zfcp_scsi_slave_alloc returned early. This can lead to kernel page faults on accessing uninitialized fields of struct zfcp_scsi_dev in zfcp_erp_lun_shutdown_wait. Take the port field of the struct to determine if slave_alloc returned early. This zfcp bug is exposed by 4e6c82b (in turn fixing f7c9c6b to be compatible with 21208ae) which can call slave_destroy for a corresponding previous slave_alloc that did not finish. This patch is based on James Bottomley's fix suggestion in http://www.spinics.net/lists/linux-scsi/msg55449.html. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@kernel.org> #2.6.38+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/scsi/zfcp_scsi.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 11f07f888223..b79576b64f45 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -55,6 +55,10 @@ static void zfcp_scsi_slave_destroy(struct scsi_device *sdev)
{
struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+ /* if previous slave_alloc returned early, there is nothing to do */
+ if (!zfcp_sdev->port)
+ return;
+
zfcp_erp_lun_shutdown_wait(sdev, "scssd_1");
put_device(&zfcp_sdev->port->dev);
}