6e5aedb932
If we have multiple requests waiting on the same target poll waitqueue, then it's quite possible to get a request triggered and get disappointed in not being able to make any progress with it. If we race in doing so, we'll potentially leave the poll request on the internal tables, but removed from the waitqueue. That means that any subsequent trigger of the poll waitqueue will not kick that request into action, causing an application to potentially wait for completion of a request that will never happen. Fix this by adding a new poll return state, IOU_POLL_REISSUE. Rather than have complicated logic for how to re-arm a given type of request, just punt it for a reissue. While in there, move the 'ret' variable to the only section where it gets used. This avoids confusion the scope of it. Cc: stable@vger.kernel.org Fixes: eb0089d629ba ("io_uring: single shot poll removal optimisation") 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.