14948e3944
Fix a race condition that can result in a ring buffer pointer being set to null while a "_show" function is reading the ring buffer's data. This problem was discussed here: https://lkml.org/lkml/2018/10/18/779 To fix the race condition, add a new mutex lock to the "hv_ring_buffer_info" struct. Add a new function, "hv_ringbuffer_pre_init()", where a channel's inbound and outbound ring_buffer_info mutex locks are initialized. Acquire/release the locks in the "hv_ringbuffer_cleanup()" function, which is where the ring buffer pointers are set to null. Acquire/release the locks in the four channel-level "_show" functions that access ring buffer data. Remove the "const" qualifier from the "vmbus_channel" parameter and the "rbi" variable of the channel-level "_show" functions so that the locks can be acquired/released in these functions. Acquire/release the locks in hv_ringbuffer_get_debuginfo(). Remove the "const" qualifier from the "hv_ring_buffer_info" parameter so that the locks can be acquired/released in this function. Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@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 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.