Linux kernel source tree
Go to file
Fred Chen d2a0fc372a tcp: fix wrong RTO timeout when received SACK reneging
This commit fix wrong RTO timeout when received SACK reneging.

When an ACK arrived pointing to a SACK reneging, tcp_check_sack_reneging()
will rearm the RTO timer for min(1/2*srtt, 10ms) into to the future.

But since the commit 62d9f1a694 ("tcp: fix TLP timer not set when
CA_STATE changes from DISORDER to OPEN") merged, the tcp_set_xmit_timer()
is moved after tcp_fastretrans_alert()(which do the SACK reneging check),
so the RTO timeout will be overwrited by tcp_set_xmit_timer() with
icsk_rto instead of 1/2*srtt.

Here is a packetdrill script to check this bug:
0     socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0    bind(3, ..., ...) = 0
+0    listen(3, 1) = 0

// simulate srtt to 100ms
+0    < S 0:0(0) win 32792 <mss 1000, sackOK,nop,nop,nop,wscale 7>
+0    > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7>
+.1    < . 1:1(0) ack 1 win 1024

+0    accept(3, ..., ...) = 4

+0    write(4, ..., 10000) = 10000
+0    > P. 1:10001(10000) ack 1

// inject sack
+.1    < . 1:1(0) ack 1 win 257 <sack 1001:10001,nop,nop>
+0    > . 1:1001(1000) ack 1

// inject sack reneging
+.1    < . 1:1(0) ack 1001 win 257 <sack 9001:10001,nop,nop>

// we expect rto fired in 1/2*srtt (50ms)
+.05    > . 1001:2001(1000) ack 1

This fix remove the FLAG_SET_XMIT_TIMER from ack_flag when
tcp_check_sack_reneging() set RTO timer with 1/2*srtt to avoid
being overwrited later.

Fixes: 62d9f1a694 ("tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN")
Signed-off-by: Fred Chen <fred.chenchen03@gmail.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-10-22 11:47:44 +01:00
arch LoongArch fixes for v6.6-rc7 2023-10-19 11:02:28 -07:00
block block: Don't invalidate pagecache for invalid falloc modes 2023-10-11 15:53:17 -06:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: sm2 - Fix crash caused by uninitialized context 2023-09-20 13:10:10 +08:00
Documentation Including fixes from bluetooth, netfilter, WiFi. 2023-10-19 12:08:18 -07:00
drivers r8152: Block future register access if register access fails 2023-10-22 11:46:18 +01:00
fs v6.6-rc7.vfs.fixes 2023-10-19 09:37:41 -07:00
include Including fixes from bluetooth, netfilter, WiFi. 2023-10-19 12:08:18 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring io-wq: fully initialize wqe before calling cpuhp_state_add_instance_nocalls() 2023-10-05 14:11:18 -06:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel v6.6-rc7.vfs.fixes 2023-10-19 09:37:41 -07:00
lib maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states 2023-09-29 17:20:46 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: slab: Do not create kmalloc caches smaller than arch_slab_minalign() 2023-10-11 15:24:49 +02:00
net tcp: fix wrong RTO timeout when received SACK reneging 2023-10-22 11:47:44 +01:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts kbuild: remove stale code for 'source' symlink in packaging scripts 2023-10-01 23:06:06 +09:00
security KEYS: trusted: Remove redundant static calls usage 2023-10-10 11:19:43 -07:00
sound TTY/Serial driver fixes for 6.6-rc6 2023-10-15 09:11:39 -07:00
tools Including fixes from bluetooth, netfilter, WiFi. 2023-10-19 12:08:18 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap MAINTAINERS: update Matthieu's email address 2023-10-05 09:34:32 -07:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 Char/Misc driver fixes for 6.6-rc6 2023-10-15 09:07:27 -07:00
Makefile Linux 6.6-rc6 2023-10-15 13:34:39 -07:00
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.