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Julian Anastasov f1ee470030 neigh: make sure used and confirmed times are valid
[ Upstream commit c1d2ecdf5e ]

Entries can linger in cache without timer for days, thanks to
the gc_thresh1 limit. As result, without traffic, the confirmed
time can be outdated and to appear to be in the future. Later,
on traffic, NUD_STALE entries can switch to NUD_DELAY and start
the timer which can see the invalid confirmed time and wrongly
switch to NUD_REACHABLE state instead of NUD_PROBE. As result,
timer is set many days in the future. This is more visible on
32-bit platforms, with higher HZ value.

Why this is a problem? While we expect unused entries to expire,
such entries stay in REACHABLE state for too long, locked in
cache. They are not expired normally, only when cache is full.

Problem and the wrong state change reported by Zhang Changzhong:

172.16.1.18 dev bond0 lladdr 0a:0e:0f:01:12:01 ref 1 used 350521/15994171/350520 probes 4 REACHABLE

350520 seconds have elapsed since this entry was last updated, but it is
still in the REACHABLE state (base_reachable_time_ms is 30000),
preventing lladdr from being updated through probe.

Fix it by ensuring timer is started with valid used/confirmed
times. Considering the valid time range is LONG_MAX jiffies,
we try not to go too much in the past while we are in
DELAY/PROBE state. There are also places that need
used/updated times to be validated while timer is not running.

Reported-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Tested-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-03-03 11:45:52 +01:00
arch ARM: dts: rockchip: add power-domains property to dp node on rk3288 2023-03-03 11:45:51 +01:00
block block, bfq: fix uaf for bfqq in bic_set_bfqq() 2023-02-09 11:26:36 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2022-12-31 13:14:24 +01:00
Documentation Documentation/hw-vuln: Add documentation for Cross-Thread Return Predictions 2023-02-14 19:18:05 +01:00
drivers IB/hfi1: Assign npages earlier 2023-03-03 11:45:52 +01:00
fs btrfs: send: limit number of clones and allocated memory size 2023-03-03 11:45:52 +01:00
include uaccess: Add speculation barrier to copy_from_user() 2023-02-25 12:06:44 +01:00
init kbuild: Add CONFIG_PAHOLE_VERSION 2023-02-25 12:06:45 +01:00
io_uring io_uring/rw: remove leftover debug statement 2023-01-24 07:22:49 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel bpf: add missing header file include 2023-02-25 12:06:46 +01:00
lib lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+ 2023-02-25 12:06:46 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/filemap: fix page end in filemap_get_read_batch 2023-02-22 12:57:10 +01:00
net neigh: make sure used and confirmed times are valid 2023-03-03 11:45:52 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2022-12-31 13:14:31 +01:00
scripts scripts/pahole-flags.sh: Use pahole-version.sh 2023-02-25 12:06:46 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-01 08:27:05 +01:00
sound ASoC: rt715-sdca: fix clock stop prepare timeout issue 2023-03-03 11:45:52 +01:00
tools selftest/lkdtm: Skip stack-entropy test if lkdtm is not available 2023-02-22 12:57:07 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt kvm: Add support for arch compat vm ioctls 2022-10-29 10:12:54 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS kbuild: Add CONFIG_PAHOLE_VERSION 2023-02-25 12:06:45 +01:00
Makefile Linux 5.15.96 2023-02-25 12:06:46 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.