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Martin KaFai Lau 1510d72863 net/mlx5e: Fix race in mlx5e_sw_stats and mlx5e_vport_stats
We have observed a sudden spike in rx/tx_packets and rx/tx_bytes
reported under /proc/net/dev.  There is a race in mlx5e_update_stats()
and some of the get-stats functions (the one that we hit is the
mlx5e_get_stats() which is called by ndo_get_stats64()).

In particular, the very first thing mlx5e_update_sw_counters()
does is 'memset(s, 0, sizeof(*s))'.  For example, if mlx5e_get_stats()
is unlucky at one point, rx_bytes and rx_packets could be 0.  One second
later, a normal (and much bigger than 0) value will be reported.

This patch is to use a 'struct mlx5e_sw_stats temp' to avoid
a direct memset zero on priv->stats.sw.

mlx5e_update_vport_counters() has a similar race.  Hence, addressed
together.  However, memset zero is removed instead because
it is not needed.

I am lucky enough to catch this 0-reset in rx multicast:
eth0: 41457665   76804   70    0    0    70          0     47085 15586634   87502    3    0    0     0       3          0
eth0: 41459860   76815   70    0    0    70          0     47094 15588376   87516    3    0    0     0       3          0
eth0: 41460577   76822   70    0    0    70          0         0 15589083   87521    3    0    0     0       3          0
eth0: 41463293   76838   70    0    0    70          0     47108 15595872   87538    3    0    0     0       3          0
eth0: 41463379   76839   70    0    0    70          0     47116 15596138   87539    3    0    0     0       3          0

v2: Remove memset zero from mlx5e_update_vport_counters()
v1: Use temp and memcpy

Fixes: 9218b44dcc ("net/mlx5e: Statistics handling refactoring")
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-24 12:15:08 -04:00
arch powerpc fixes for 4.11 #8 2017-04-21 09:34:45 -07:00
block blk-mq: fix potential oops with polling and blk-mq scheduler 2017-04-20 14:53:28 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-04-18 09:03:50 -07:00
Documentation pci-v4.11-fixes-5 2017-04-21 09:26:34 -07:00
drivers net/mlx5e: Fix race in mlx5e_sw_stats and mlx5e_vport_stats 2017-04-24 12:15:08 -04:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Fix a 4.11 regression that triggers a BUG() on an attempt to use an 2017-04-21 16:37:48 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-04-21 13:20:47 -07:00
init mm: move mm_percpu_wq initialization earlier 2017-03-31 17:13:30 -07:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel While continuing my development, I uncovered two more small bugs. 2017-04-20 12:30:10 -07:00
lib sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL 2017-04-18 13:11:07 -07:00
mm mm: prevent NR_ISOLATE_* stats from going negative 2017-04-20 15:30:18 -07:00
net netpoll: Check for skb->queue_mapping 2017-04-21 15:45:19 -04:00
samples statx: Include a mask for stx_attributes in struct statx 2017-04-03 01:06:00 -04:00
scripts Kbuild fixes for v4.11 2017-04-05 08:37:28 -07:00
security KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings 2017-04-18 15:31:49 +01:00
sound ALSA: hda - fix a problem for lineout on a Dell AIO machine 2017-03-31 10:58:26 +02:00
tools bpf: Fix values type used in test_maps 2017-04-21 15:16:46 -04:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.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 Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
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 bpf, doc: update bpf maintainers entry 2017-04-21 15:25:10 -04:00
Makefile Linux 4.11-rc7 2017-04-16 13:00:18 -07:00
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.