SCSI: zfcp: return early from slave_destroy if slave_alloc returned early
authorSteffen Maier <maier@linux.vnet.ibm.com>
Fri, 18 Nov 2011 19:00:40 +0000 (20:00 +0100)
committerRohan Somvanshi <rsomvanshi@nvidia.com>
Wed, 11 Jan 2012 17:23:54 +0000 (09:23 -0800)
commit54d95d962fe127d3460ff1d6610331b7626c7523
treee5119bf6fceaf0972be6ee71314d43c2f63a4580
parent2be95e9bbff7680659d9a17f5d04d2c2c638edb9
SCSI: zfcp: return early from slave_destroy if slave_alloc returned early

commit 44f747fff6e9f027a4866c1a6864e26ae7c510c8 upstream.

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>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Change-Id: I4e8a616faeb24d919c5249039394fcfa78365986
Reviewed-on: http://git-master/r/74163
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>
Tested-by: Varun Wadekar <vwadekar@nvidia.com>
drivers/s390/scsi/zfcp_scsi.c