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Chris Leech 6f8830f5bb scsi: libiscsi: add lock around task lists to fix list corruption regression
There's a rather long standing regression from the commit "libiscsi:
Reduce locking contention in fast path"

Depending on iSCSI target behavior, it's possible to hit the case in
iscsi_complete_task where the task is still on a pending list
(!list_empty(&task->running)).  When that happens the task is removed
from the list while holding the session back_lock, but other task list
modification occur under the frwd_lock.  That leads to linked list
corruption and eventually a panicked system.

Rather than back out the session lock split entirely, in order to try
and keep some of the performance gains this patch adds another lock to
maintain the task lists integrity.

Major enterprise supported kernels have been backing out the lock split
for while now, thanks to the efforts at IBM where a lab setup has the
most reliable reproducer I've seen on this issue.  This patch has been
tested there successfully.

Signed-off-by: Chris Leech <cleech@redhat.com>
Fixes: 659743b02c ("[SCSI] libiscsi: Reduce locking contention in fast path")
Reported-by: Prashantha Subbarao <psubbara@us.ibm.com>
Reviewed-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-02-28 22:05:22 -05:00
Documentation TTY/Serial driver patches for 4.11-rc1 2017-02-22 12:17:25 -08:00
arch TTY/Serial driver patches for 4.11-rc1 2017-02-22 12:17:25 -08:00
block for-4.11/linus-merge-signed 2017-02-21 10:57:33 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: algif_aead - Fix kernel panic on list_del 2017-02-03 17:45:48 +08:00
drivers scsi: libiscsi: add lock around task lists to fix list corruption regression 2017-02-28 22:05:22 -05:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
include scsi: libiscsi: add lock around task lists to fix list corruption regression 2017-02-28 22:05:22 -05:00
init char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
lib TTY/Serial driver patches for 4.11-rc1 2017-02-22 12:17:25 -08:00
mm arm64 updates for 4.11: 2017-02-22 10:46:44 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
scripts char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
security driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
sound ALSA: hda - adding a new NV HDMI/DP codec ID in the driver 2017-02-09 08:57:47 +01:00
tools staging/iio driver patches for 4.11-rc1 2017-02-22 12:14:01 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM updates for 4.10-rc4 2017-01-17 15:04:59 +01:00
.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 mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework. 2017-02-22 19:10:59 -05:00
Makefile Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 12:21:13 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

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.