mirror of
https://github.com/torvalds/linux.git
synced 2026-01-25 15:03:52 +08:00
bac76cf898
We have some problem closing zero-window fin-wait-1 tcp sockets in our
environment. This patch come from the investigation.
Previously tcp_abort only sends out reset and calls tcp_done when the
socket is not SOCK_DEAD, aka orphan. For orphan socket, it will only
purging the write queue, but not close the socket and left it to the
timer.
While purging the write queue, tp->packets_out and sk->sk_write_queue
is cleared along the way. However tcp_retransmit_timer have early
return based on !tp->packets_out and tcp_probe_timer have early
return based on !sk->sk_write_queue.
This caused ICSK_TIME_RETRANS and ICSK_TIME_PROBE0 not being resched
and socket not being killed by the timers, converting a zero-windowed
orphan into a forever orphan.
This patch removes the SOCK_DEAD check in tcp_abort, making it send
reset to peer and close the socket accordingly. Preventing the
timer-less orphan from happening.
According to Lorenzo's email in the v1 thread, the check was there to
prevent force-closing the same socket twice. That situation is handled
by testing for TCP_CLOSE inside lock, and returning -ENOENT if it is
already closed.
The -ENOENT code comes from the associate patch Lorenzo made for
iproute2-ss; link attached below, which also conform to RFC 9293.
At the end of the patch, tcp_write_queue_purge(sk) is removed because it
was already called in tcp_done_with_error().
p.s. This is the same patch with v2. Resent due to mis-labeled "changes
requested" on patchwork.kernel.org.
Link: https://patchwork.ozlabs.org/project/netdev/patch/1450773094-7978-3-git-send-email-lorenzo@google.com/
Fixes: c1e64e298b ("net: diag: Support destroying TCP sockets.")
Signed-off-by: Xueming Feng <kuro@kuroa.me>
Tested-by: Lorenzo Colitti <lorenzo@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20240826102327.1461482-1-kuro@kuroa.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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 reStructuredText 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.