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Lu Wei 02f8dfee75 tcp: prohibit TCP_REPAIR_OPTIONS if data was already sent [ Upstream commit `0c175da7b0` ] If setsockopt with option name of TCP_REPAIR_OPTIONS and opt_code of TCPOPT_SACK_PERM is called to enable sack after data is sent and dupacks are received , it will trigger a warning in function tcp_verify_left_out() as follows: ============================================ WARNING: CPU: 8 PID: 0 at net/ipv4/tcp_input.c:2132 tcp_timeout_mark_lost+0x154/0x160 tcp_enter_loss+0x2b/0x290 tcp_retransmit_timer+0x50b/0x640 tcp_write_timer_handler+0x1c8/0x340 tcp_write_timer+0xe5/0x140 call_timer_fn+0x3a/0x1b0 __run_timers.part.0+0x1bf/0x2d0 run_timer_softirq+0x43/0xb0 __do_softirq+0xfd/0x373 __irq_exit_rcu+0xf6/0x140 The warning is caused in the following steps: 1. a socket named socketA is created 2. socketA enters repair mode without build a connection 3. socketA calls connect() and its state is changed to TCP_ESTABLISHED directly 4. socketA leaves repair mode 5. socketA calls sendmsg() to send data, packets_out and sack_outs(dup ack receives) increase 6. socketA enters repair mode again 7. socketA calls setsockopt with TCPOPT_SACK_PERM to enable sack 8. retransmit timer expires, it calls tcp_timeout_mark_lost(), lost_out increases 9. sack_outs + lost_out > packets_out triggers since lost_out and sack_outs increase repeatly In function tcp_timeout_mark_lost(), tp->sacked_out will be cleared if Step7 not happen and the warning will not be triggered. As suggested by Denis and Eric, TCP_REPAIR_OPTIONS should be prohibited if data was already sent. socket-tcp tests in CRIU has been tested as follows: $ sudo ./test/zdtm.py run -t zdtm/static/socket-tcp* --keep-going \ --ignore-taint socket-tcp* represent all socket-tcp tests in test/zdtm/static/. Fixes: `b139ba4e90` ("tcp: Repair connection-time negotiated parameters") Signed-off-by: Lu Wei <luwei32@huawei.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-11-16 09:57:11 +01:00
arch	KVM: s390: pv: don't allow userspace to set the clock under PV	2022-11-16 09:57:10 +01:00
block	block, bfq: protect 'bfqd->queued' by 'bfqd->lock'	2022-11-10 18:14:24 +01:00
certs	certs/blacklist_hashes.c: fix const confusion in certs blacklist	2022-06-22 14:13:17 +02:00
crypto	crypto: akcipher - default implementation for setting a private key	2022-10-26 13:25:42 +02:00
Documentation	KVM: s390: pv: don't allow userspace to set the clock under PV	2022-11-16 09:57:10 +01:00
drivers	drm/vc4: Fix missing platform_unregister_drivers() call in vc4_drm_register()	2022-11-16 09:57:11 +01:00
fs	fuse: fix readdir cache race	2022-11-16 09:57:07 +01:00
include	capabilities: fix undefined behavior in bit shift for CAP_TO_MASK	2022-11-16 09:57:10 +01:00
init	Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug	2022-06-09 10:21:25 +02:00
ipc	ipc: remove memcg accounting for sops objects in do_semtimedop()	2022-11-10 18:14:29 +01:00
kernel	bpf: Fix wrong reg type conversion in release_reference()	2022-11-16 09:57:09 +01:00
lib	dyndbg: drop EXPORTed dynamic_debug_exec_queries	2022-10-26 13:25:34 +02:00
LICENSES	LICENSES/deprecated: add Zlib license text	2020-09-16 14:33:49 +02:00
mm	mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages	2022-11-03 23:57:50 +09:00
net	tcp: prohibit TCP_REPAIR_OPTIONS if data was already sent	2022-11-16 09:57:11 +01:00
samples	x86: Prepare inline-asm for straight-line-speculation	2022-07-25 11:26:29 +02:00
scripts	kbuild: Add skip_encoding_btf_enum64 option to pahole	2022-10-28 12:57:12 +02:00
security	capabilities: fix potential memleak on error path from vfs_getxattr_alloc()	2022-11-10 18:14:26 +01:00
sound	ALSA: usb-audio: Add quirks for MacroSilicon MS2100/MS2106 devices	2022-11-10 18:14:24 +01:00
tools	bpftool: Fix NULL pointer dereference when pin {PROG, MAP, LINK} without FILE	2022-11-16 09:57:08 +01:00
usr	usr/include/Makefile: add linux/nfc.h to the compile-test coverage	2022-02-01 17:25:48 +01:00
virt	kvm: Add support for arch compat vm ioctls	2022-10-30 09:41:15 +01:00
.clang-format	RDMA 5.10 pull request	2020-10-17 11:18:18 -07:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	kbuild: generate Module.symvers only when vmlinux exists	2021-05-19 10:12:59 +02:00
.mailmap	mailmap: add two more addresses of Uwe Kleine-König	2020-12-06 10:19:07 -08:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Jason Cooper to CREDITS	2020-11-30 10:20:34 +01:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	MAINTAINERS: add Amir as xfs maintainer for 5.10.y	2022-07-02 16:39:22 +02:00
Makefile	Linux 5.10.154	2022-11-10 18:14:30 +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.