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98693e0897
Thanks to a device generating an ACS violation during bus reset,
lockdep reported the following circular locking issue:
CPU0: SET_IRQS (MSI/X): holds igate, acquires memory_lock
CPU1: HOT_RESET: holds memory_lock, acquires pci_bus_sem
CPU2: AER: holds pci_bus_sem, acquires igate
This results in a potential 3-way deadlock.
Remove the pci_bus_sem->igate leg of the triangle by using RCU
to peek at the eventfd rather than locking it with igate.
Fixes: 3be3a074cf ("vfio-pci: Don't use device_lock around AER interrupt setup")
Signed-off-by: Alex Williamson <alex.williamson@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20251124223623.2770706-1-alex@shazbot.org
Signed-off-by: Alex Williamson <alex@shazbot.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 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.