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Jason Xing b2c55af89b net: fix the RTO timer retransmitting skb every 1ms if linear option is enabled
commit e4dd0d3a2f upstream.

In the real workload, I encountered an issue which could cause the RTO
timer to retransmit the skb per 1ms with linear option enabled. The amount
of lost-retransmitted skbs can go up to 1000+ instantly.

The root cause is that if the icsk_rto happens to be zero in the 6th round
(which is the TCP_THIN_LINEAR_RETRIES value), then it will always be zero
due to the changed calculation method in tcp_retransmit_timer() as follows:

icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);

Above line could be converted to
icsk->icsk_rto = min(0 << 1, TCP_RTO_MAX) = 0

Therefore, the timer expires so quickly without any doubt.

I read through the RFC 6298 and found that the RTO value can be rounded
up to a certain value, in Linux, say TCP_RTO_MIN as default, which is
regarded as the lower bound in this patch as suggested by Eric.

Fixes: 36e31b0af5 ("net: TCP thin linear timeouts")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-23 17:52:42 +02:00
arch arm64/ptrace: Ensure that SME is set up for target when writing SSVE state 2023-08-23 17:52:41 +02:00
block blk-crypto: dynamically allocate fallback profile 2023-08-23 17:52:39 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:21:42 +02:00
Documentation iommu/amd: Introduce Disable IRTE Caching Support 2023-08-23 17:52:21 +02:00
drivers drm/nouveau/disp: fix use-after-free in error handling of nouveau_connector_create 2023-08-23 17:52:42 +02:00
fs cifs: Release folio lock on fscache read hit. 2023-08-23 17:52:39 +02:00
include net: do not allow gso_size to be set to GSO_BY_FRAGS 2023-08-23 17:52:35 +02:00
init x86/mm: Initialize text poking earlier 2023-08-08 20:03:49 +02:00
io_uring io_uring: correct check for O_TMPFILE 2023-08-16 18:27:24 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel sched/fair: Remove capacity inversion detection 2023-08-23 17:52:41 +02:00
lib debugobjects: Recheck debug_objects_enabled before reporting 2023-08-11 12:08:23 +02:00
LICENSES
mm hugetlb: do not clear hugetlb dtor until allocating vmemmap 2023-08-23 17:52:41 +02:00
net net: fix the RTO timer retransmitting skb every 1ms if linear option is enabled 2023-08-23 17:52:42 +02:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:49:44 +02:00
scripts gcc-plugins: Reorganize gimple includes for GCC 13 2023-08-16 18:27:20 +02:00
security security: keys: Modify mismatched function name 2023-07-27 08:50:43 +02:00
sound ASoC: amd: vangogh: select CONFIG_SND_AMD_ACP_CONFIG 2023-08-23 17:52:40 +02:00
tools selftests: mirror_gre_changes: Tighten up the TTL test match 2023-08-23 17:52:33 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:24:08 +02:00
.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
.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
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
MAINTAINERS smb: move client and server files to common directory fs/smb 2023-06-28 11:12:40 +02:00
Makefile Linux 6.1.46 2023-08-16 18:27:31 +02:00
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.