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17393fa7b7
I'm observing very frequent self-tests failures in case of fallback when
running on a CONFIG_PREEMPT kernel.
The root cause is that subflow_sched_work_if_closed() closes any subflow
as soon as it is half-closed and has no incoming data pending.
That works well for regular subflows - MPTCP needs bi-directional
connectivity to operate on a given subflow - but for fallback socket is
race prone.
When TCP peer closes the connection before the MPTCP one,
subflow_sched_work_if_closed() will schedule the MPTCP worker to
gracefully close the subflow, and shortly after will do another schedule
to inject and process a dummy incoming DATA_FIN.
On CONFIG_PREEMPT kernel, the MPTCP worker can kick-in and close the
fallback subflow before subflow_sched_work_if_closed() is able to create
the dummy DATA_FIN, unexpectedly interrupting the transfer.
Address the issue explicitly avoiding closing fallback subflows on when
the peer is only half-closed.
Note that, when the subflow is able to create the DATA_FIN before the
worker invocation, the worker will change the msk state before trying to
close the subflow and will skip the latter operation as the msk will not
match anymore the precondition in __mptcp_close_subflow().
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 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.