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D. Wythe e6d71b437a net/smc: avoid data corruption caused by decline
We found a data corruption issue during testing of SMC-R on Redis
applications.

The benchmark has a low probability of reporting a strange error as
shown below.

"Error: Protocol error, got "\xe2" as reply type byte"

Finally, we found that the retrieved error data was as follows:

0xE2 0xD4 0xC3 0xD9 0x04 0x00 0x2C 0x20 0xA6 0x56 0x00 0x16 0x3E 0x0C
0xCB 0x04 0x02 0x01 0x00 0x00 0x20 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0xE2

It is quite obvious that this is a SMC DECLINE message, which means that
the applications received SMC protocol message.
We found that this was caused by the following situations:

client                  server
        ¦  clc proposal
        ------------->
        ¦  clc accept
        <-------------
        ¦  clc confirm
        ------------->
wait llc confirm
			send llc confirm
        ¦failed llc confirm
        ¦   x------
(after 2s)timeout
                        wait llc confirm rsp

wait decline

(after 1s) timeout
                        (after 2s) timeout
        ¦   decline
        -------------->
        ¦   decline
        <--------------

As a result, a decline message was sent in the implementation, and this
message was read from TCP by the already-fallback connection.

This patch double the client timeout as 2x of the server value,
With this simple change, the Decline messages should never cross or
collide (during Confirm link timeout).

This issue requires an immediate solution, since the protocol updates
involve a more long-term solution.

Fixes: 0fb0b02bd6 ("net/smc: adapt SMC client code to use the LLC flow")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-11-22 12:10:19 +00:00
arch acpi/processor: sanitize _OSC/_PDC capabilities for Xen dom0 2023-11-13 07:22:00 +01:00
block blk-core: use pr_warn_ratelimited() in bio_check_ro() 2023-11-07 08:15:23 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation docs: netdev: try to guide people on dealing with silence 2023-11-21 14:35:43 -08:00
drivers nfc: virtual_ncidev: Add variable to check if ndev is running 2023-11-22 10:55:48 +00:00
fs for-6.7-rc1-tag 2023-11-13 09:09:12 -08:00
include bpf: keep track of max number of bpf_loop callback iterations 2023-11-20 18:36:40 -08:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring: do not clamp read length for multishot read 2023-11-06 13:41:58 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel bpf: keep track of max number of bpf_loop callback iterations 2023-11-20 18:36:40 -08:00
lib Zstd fixes for v6.7 2023-11-14 23:35:31 -05:00
LICENSES
mm memblock: report failures when memblock_can_resize is not set 2023-11-08 09:40:13 -08:00
net net/smc: avoid data corruption caused by decline 2023-11-22 12:10:19 +00:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts kernel hardening fixes for v6.7-rc2 2023-11-14 23:47:12 -05:00
security + Features 2023-11-03 09:48:17 -10:00
sound sound fixes for 6.7-rc1 2023-11-10 11:57:51 -08:00
tools selftests/bpf: check if max number of bpf_loop iterations is tracked 2023-11-20 18:36:40 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
.rustfmt.toml
COPYING
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Add indirect_call_wrapper.h to NETWORKING [GENERAL] 2023-11-21 15:21:18 +01:00
Makefile Linux 6.7-rc1 2023-11-12 16:19:07 -08:00
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.