f0e20b8943
There is a recipe to deadlock the kernel: submit a timeout sqe with a linked_timeout (e.g. test_single_link_timeout_ception() from liburing), and SIGKILL the process. Then, io_kill_timeouts() takes @ctx->completion_lock, but the timeout isn't flagged with REQ_F_COMP_LOCKED, and will try to double grab it during io_put_free() to cancel the linked timeout. Probably, the same can happen with another io_kill_timeout() call site, that is io_commit_cqring(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.