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Device lock bites again; if a device .remove() callback races a user calling ioctl(VFIO_GROUP_GET_DEVICE_FD), the unbind request will hold the device lock, but the user ioctl may have already taken a vfio_device reference. In the case of a PCI device, the initial open will attempt to reset the device, which again attempts to get the device lock, resulting in deadlock. Use the trylock PCI reset interface and return error on the open path if reset fails due to lock contention. Link: https://lkml.org/lkml/2017/7/25/381 Reported-by: Wen Congyang <wencongyang2@huawei.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.