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Yonghong Song 853223c2ca bpf: fix rcu lockdep warning for lpm_trie map_free callback
[ upstream commit 6c5f61023c ]

Commit 9a3efb6b66 ("bpf: fix memory leak in lpm_trie map_free callback function")
fixed a memory leak and removed unnecessary locks in map_free callback function.
Unfortrunately, it introduced a lockdep warning. When lockdep checking is turned on,
running tools/testing/selftests/bpf/test_lpm_map will have:

  [   98.294321] =============================
  [   98.294807] WARNING: suspicious RCU usage
  [   98.295359] 4.16.0-rc2+ #193 Not tainted
  [   98.295907] -----------------------------
  [   98.296486] /home/yhs/work/bpf/kernel/bpf/lpm_trie.c:572 suspicious rcu_dereference_check() usage!
  [   98.297657]
  [   98.297657] other info that might help us debug this:
  [   98.297657]
  [   98.298663]
  [   98.298663] rcu_scheduler_active = 2, debug_locks = 1
  [   98.299536] 2 locks held by kworker/2:1/54:
  [   98.300152]  #0:  ((wq_completion)"events"){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0
  [   98.301381]  #1:  ((work_completion)(&map->work)){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0

Since actual trie tree removal happens only after no other
accesses to the tree are possible, replacing
  rcu_dereference_protected(*slot, lockdep_is_held(&trie->lock))
with
  rcu_dereference_protected(*slot, 1)
fixed the issue.

Fixes: 9a3efb6b66 ("bpf: fix memory leak in lpm_trie map_free callback function")
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-11 16:23:21 +01:00
Documentation doc: Change the min default value of tcp_wmem/tcp_rmem. 2018-03-08 22:41:13 -08:00
arch ARM: dts: LogicPD Torpedo: Fix I2C1 pinmux 2018-03-08 22:41:26 -08:00
block blk-mq: don't call io sched's .requeue_request when requeueing rq to ->dispatch 2018-03-08 22:41:20 -08:00
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
drivers nvme-rdma: don't suppress send completions 2018-03-08 22:41:26 -08:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs direct-io: Fix sleep in atomic due to sync AIO 2018-03-08 22:41:06 -08:00
include nospec: Allow index argument to have const-qualified type 2018-03-08 22:41:22 -08:00
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 bpf: fix rcu lockdep warning for lpm_trie map_free callback 2018-03-11 16:23:21 +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 tcp: purge write queue upon RST 2018-03-08 22:41:17 -08:00
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 ALSA: hda - Fix pincfg at resume on Lenovo T470 dock 2018-03-08 22:41:02 -08:00
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: mmu: Fix overlap between public and private memslots 2018-03-08 22:41:24 -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 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
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 4.14.25 2018-03-08 22:41:27 -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.