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Jon Maloy e88f2be832 tipc: fix race condition at topology server receive
We have identified a race condition during reception of socket
events and messages in the topology server.

- The function tipc_close_conn() is releasing the corresponding
  struct tipc_subscriber instance without considering that there
  may still be items in the receive work queue. When those are
  scheduled, in the function tipc_receive_from_work(), they are
  using the subscriber pointer stored in struct tipc_conn, without
  first checking if this is valid or not. This will sometimes
  lead to crashes, as the next call of tipc_conn_recvmsg() will
  access the now deleted item.
  We fix this by making the usage of this pointer conditional on
  whether the connection is active or not. I.e., we check the condition
  test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg().

- Since the two functions may be running on different cores, the
  condition test described above is not enough. tipc_close_conn()
  may come in between and delete the subscriber item after the condition
  test is done, but before tipc_conn_recv_msg() is finished. This
  happens less frequently than the problem described above, but leads
  to the same symptoms.

  We fix this by using the existing sk_callback_lock for mutual
  exclusion in the two functions. In addition, we have to move
  a call to tipc_conn_terminate() outside the mentioned lock to
  avoid deadlock.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-16 14:42:41 -05:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-11 22:13:42 -05:00
block block: drain queue before waiting for q_usage_counter becoming zero 2018-01-05 09:09:48 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-01-05 12:10:06 -08:00
Documentation mlxsw: documentation: Add resources ABI documentation 2018-01-16 14:15:35 -05:00
drivers net: aquantia: Fix internal stats calculation on rx 2018-01-16 14:40:01 -05:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-09 10:37:00 -05:00
include devlink: Add relation between dpipe and resource 2018-01-16 14:15:34 -05:00
init Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2018-01-10 11:17:21 -05:00
ipc Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-11 22:13:42 -05:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-11 22:13:42 -05:00
mm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-06 17:13:21 -08:00
net tipc: fix race condition at topology server receive 2018-01-16 14:42:41 -05:00
samples samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB 2018-01-11 01:02:25 +01:00
scripts Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-15 11:44:59 -08:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-09 10:37:00 -05:00
sound ALSA: pcm: Allow aborting mutex lock at OSS read/write loops 2018-01-08 16:40:26 +01:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-11 22:13:42 -05:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM/ARM Fixes for v4.15, Round 2 2017-12-18 12:57:43 +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 Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS wireless-drivers-next patches for 4.16 2018-01-15 14:46:16 -05:00
Makefile Linux 4.15-rc7 2018-01-07 14:22:41 -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.