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Steffen Maier 2dfa6688aa scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send
Dan Carpenter kindly reported:
<quote>
The patch d27a7cb919: "zfcp: trace on request for open and close of
WKA port" from Aug 10, 2016, leads to the following static checker
warning:

	drivers/s390/scsi/zfcp_fsf.c:1615 zfcp_fsf_open_wka_port()
	warn: 'req' was already freed.

drivers/s390/scsi/zfcp_fsf.c
  1609          zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT);
  1610          retval = zfcp_fsf_req_send(req);
  1611          if (retval)
  1612                  zfcp_fsf_req_free(req);
                                          ^^^
Freed.

  1613  out:
  1614          spin_unlock_irq(&qdio->req_q_lock);
  1615          if (req && !IS_ERR(req))
  1616                  zfcp_dbf_rec_run_wka("fsowp_1", wka_port, req->req_id);
                                                                  ^^^^^^^^^^^
Use after free.

  1617          return retval;
  1618  }

Same thing for zfcp_fsf_close_wka_port() as well.
</quote>

Rather than relying on req being NULL (or ERR_PTR) for all cases where
we don't want to trace or should not trace,
simply check retval which is unconditionally initialized with -EIO != 0
and it can only become 0 on successful retval = zfcp_fsf_req_send(req).
With that we can also remove the then again unnecessary unconditional
initialization of req which was introduced with that earlier commit.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: d27a7cb919 ("zfcp: trace on request for open and close of WKA port")
Cc: <stable@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-02-09 19:28:19 -05:00
arch arm64 updates for 4.10: 2016-12-13 16:39:21 -08:00
block SCSI misc on 20161213 2016-12-14 10:49:33 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-10 16:21:55 -05:00
Documentation . various fixes and improvements to request-based DM and DM multipath 2016-12-14 11:01:00 -08:00
drivers scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send 2017-02-09 19:28:19 -05:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs This merge request includes the dax-4.0-iomap-pmd branch which is 2016-12-14 09:17:42 -08:00
include scsi: libfc: Fix variable name in fc_set_wwpn 2017-01-16 15:43:02 -05:00
init Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2016-12-13 12:59:57 -08:00
ipc sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q 2016-11-21 10:29:01 +01:00
kernel Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2016-12-13 12:59:57 -08:00
lib Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2016-12-14 10:58:17 -08:00
mm This merge request includes the dax-4.0-iomap-pmd branch which is 2016-12-14 09:17:42 -08:00
net Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:25:04 -08:00
samples VFIO updates for v4.10-rc1 2016-12-13 09:23:56 -08:00
scripts Char/Misc driver patches for 4.10-rc1 2016-12-13 12:11:01 -08:00
security Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:56:15 -08:00
sound Main pull request for drm for 4.10 kernel 2016-12-13 09:35:09 -08:00
tools arm64 updates for 4.10: 2016-12-13 16:39:21 -08:00
usr usr/Kconfig: make initrd compression algorithm selection not expert 2014-12-13 12:42:52 -08:00
virt Small release, the most interesting stuff is x86 nested virt improvements. 2016-12-13 15:47:02 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-10-15 09:26:12 -07:00
COPYING
CREDITS Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 15:23:02 -08:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS scsi: Update 3ware driver email addresses 2016-12-14 15:25:12 -05:00
Makefile Linux 4.9 2016-12-11 11:17:54 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.