superrob1500
/
mirror-linux
mirror of https://github.com/torvalds/linux
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
Linux kernel source tree
1,139,289 Commits
1 Branch
922 Tags
8.5 GiB
C 97.1%
Assembly 1%
Shell 0.6%
Rust 0.4%
Python 0.4%
Other 0.3%
 
 
 
 
 
 
Go to file
Sebastian Andrzej Siewior b5259dcfa3 hsr: Synchronize sending frames to have always incremented outgoing seq nr. 
[ Upstream commit 06afd2c31d ]

Sending frames via the hsr (master) device requires a sequence number
which is tracked in hsr_priv::sequence_nr and protected by
hsr_priv::seqnr_lock. Each time a new frame is sent, it will obtain a
new id and then send it via the slave devices.
Each time a packet is sent (via hsr_forward_do()) the sequence number is
checked via hsr_register_frame_out() to ensure that a frame is not
handled twice. This make sense for the receiving side to ensure that the
frame is not injected into the stack twice after it has been received
from both slave ports.

There is no locking to cover the sending path which means the following
scenario is possible:

  CPU0				CPU1
  hsr_dev_xmit(skb1)		hsr_dev_xmit(skb2)
   fill_frame_info()             fill_frame_info()
    hsr_fill_frame_info()         hsr_fill_frame_info()
     handle_std_frame()            handle_std_frame()
      skb1's sequence_nr = 1
                                    skb2's sequence_nr = 2
   hsr_forward_do()              hsr_forward_do()

                                   hsr_register_frame_out(, 2)  // okay, send)

    hsr_register_frame_out(, 1) // stop, lower seq duplicate

Both skbs (or their struct hsr_frame_info) received an unique id.
However since skb2 was sent before skb1, the higher sequence number was
recorded in hsr_register_frame_out() and the late arriving skb1 was
dropped and never sent.

This scenario has been observed in a three node HSR setup, with node1 +
node2 having ping and iperf running in parallel. From time to time ping
reported a missing packet. Based on tracing that missing ping packet did
not leave the system.

It might be possible (didn't check) to drop the sequence number check on
the sending side. But if the higher sequence number leaves on wire
before the lower does and the destination receives them in that order
and it will drop the packet with the lower sequence number and never
inject into the stack.
Therefore it seems the only way is to lock the whole path from obtaining
the sequence number and sending via dev_queue_xmit() and assuming the
packets leave on wire in the same order (and don't get reordered by the
NIC).

Cover the whole path for the master interface from obtaining the ID
until after it has been forwarded via hsr_forward_skb() to ensure the
skbs are sent to the NIC in the order of the assigned sequence numbers.

Fixes: f421436a59 ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2022-12-31 13:32:22 +01:00
Documentation ASoC: dt-bindings: wcd9335: fix reset line polarity in example 2022-12-31 13:32:18 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch x86/boot: Skip realmode init code when running as Xen PV guest 2022-12-31 13:32:16 +01:00
block block: clear ->slave_dir when dropping the main slave_dir reference 2022-12-31 13:32:12 +01:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
drivers clk: qcom: clk-krait: fix wrong div2 functions 2022-12-31 13:32:21 +01:00
fs NFS: Fix an Oops in nfs_d_automount() 2022-12-31 13:32:18 +01:00
include bpf, sockmap: Fix missing BPF_F_INGRESS flag when using apply_bytes 2022-12-31 13:32:20 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-11-22 22:42:38 +09:00
io_uring io_uring: Fix a null-ptr-deref in io_tctx_exit_cb() 2022-12-07 06:45:20 -07:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel bpf: Pin the start cgroup in cgroup_iter_seq_init() 2022-12-31 13:32:13 +01:00
lib lib/notifier-error-inject: fix error when writing -errno to debugfs file 2022-12-31 13:31:58 +01:00
mm 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
net hsr: Synchronize sending frames to have always incremented outgoing seq nr. 2022-12-31 13:32:22 +01:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples samples/bpf: Fix MAC address swapping in xdp2_kern 2022-12-31 13:32:03 +01:00
scripts - Handle different output of readelf on different distros running 2022-11-27 12:08:17 -08:00
security ima: Fix misuse of dereference of pointer in template_desc_init_fields() 2022-12-31 13:32:12 +01:00
sound ASoC: pcm512x: Fix PM disable depth imbalance in pcm512x_probe 2022-12-31 13:32:19 +01:00
tools netfilter: conntrack: set icmpv6 redirects as RELATED 2022-12-31 13:32:19 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt Merge branch 'kvm-dwmw2-fixes' into HEAD 2022-11-23 18:59:45 -05:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
…
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
Makefile Linux 6.1.1 2022-12-21 17:48:12 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.