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Erez Shitrit ba28394c57 IB/ipoib: Fix race condition in neigh creation
[ Upstream commit 16ba3defb8 ]

When using enhanced mode for IPoIB, two threads may execute xmit in
parallel to two different TX queues while the target is the same.
In this case, both of them will add the same neighbor to the path's
neigh link list and we might see the following message:

  list_add double add: new=ffff88024767a348, prev=ffff88024767a348...
  WARNING: lib/list_debug.c:31__list_add_valid+0x4e/0x70
  ipoib_start_xmit+0x477/0x680 [ib_ipoib]
  dev_hard_start_xmit+0xb9/0x3e0
  sch_direct_xmit+0xf9/0x250
  __qdisc_run+0x176/0x5d0
  __dev_queue_xmit+0x1f5/0xb10
  __dev_queue_xmit+0x55/0xb10

Analysis:
Two SKB are scheduled to be transmitted from two cores.
In ipoib_start_xmit, both gets NULL when calling ipoib_neigh_get.
Two calls to neigh_add_path are made. One thread takes the spin-lock
and calls ipoib_neigh_alloc which creates the neigh structure,
then (after the __path_find) the neigh is added to the path's neigh
link list. When the second thread enters the critical section it also
calls ipoib_neigh_alloc but in this case it gets the already allocated
ipoib_neigh structure, which is already linked to the path's neigh
link list and adds it again to the list. Which beside of triggering
the list, it creates a loop in the linked list. This loop leads to
endless loop inside path_rec_completion.

Solution:
Check list_empty(&neigh->list) before adding to the list.
Add a similar fix in "ipoib_multicast.c::ipoib_mcast_send"

Fixes: b63b70d877 ('IPoIB: Use a private hash table for path lookup in xmit path')
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-03-03 10:24:33 +01:00
arch perf/x86/intel: Plug memory leak in intel_pmu_init() 2018-03-03 10:24:31 +01:00
block blk_rq_map_user_iov: fix error override 2018-02-25 11:07:49 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: af_alg - Fix race around ctx->rcvused by making it atomic_t 2018-03-03 10:24:29 +01:00
Documentation ext4: correct documentation for grpid mount option 2018-02-22 15:42:26 +01:00
drivers IB/ipoib: Fix race condition in neigh creation 2018-03-03 10:24:33 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs btrfs: Fix flush bio leak 2018-03-03 10:24:32 +01:00
include crypto: af_alg - Fix race around ctx->rcvused by making it atomic_t 2018-03-03 10:24:29 +01:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel genirq: Guard handle_bad_irq log messages 2018-03-03 10:24:31 +01:00
lib lib/mpi: Fix umul_ppmm() for MIPS64r6 2018-03-03 10:24:29 +01:00
mm mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2018-03-03 10:24:21 +01:00
net ip6_tunnel: allow ip6gre dev mtu to be set below 1280 2018-03-03 10:24:32 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts scripts/kernel-doc: Don't fail with status != 0 if error encountered with -none 2018-02-25 11:07:58 +01:00
security selinux: skip bounded transition processing if the policy isn't loaded 2018-02-25 11:07:49 +01:00
sound ASoC: rsnd: fixup ADG register mask 2018-03-03 10:24:28 +01:00
tools perf test: Fix test 21 for s390x 2018-02-25 11:07:55 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: Fix spinlock acquisition in vgic_set_owner 2018-02-25 11:07:56 +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: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
Makefile Linux 4.14.23 2018-02-28 10:19:45 +01:00
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.