Chris Wilson 968a85b19d drm/i915/gvt: Prevent use-after-free in ppgtt_free_all_spt()
ppgtt_free_all_spt() iterates the radixtree as it is deleting it,
forgoing all protection against the leaves being freed in the process
(leaving the iter pointing into the void).

A minimal fix seems to be to use the available post_shadow_list to
decompose the tree into a list prior to destroying the radixtree.

Alerted by the sparse warnings:

drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces)
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    expected void **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    got void [noderef] <asn:4> **
drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces)
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    expected void **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    got void [noderef] <asn:4> **
drivers/gpu/drm/i915/gvt/gtt.c:758:45: warning: incorrect type in argument 1 (different address spaces)
drivers/gpu/drm/i915/gvt/gtt.c:758:45:    expected void [noderef] <asn:4> **slot
drivers/gpu/drm/i915/gvt/gtt.c:758:45:    got void **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in argument 1 (different address spaces)
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    expected void [noderef] <asn:4> **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    got void **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces)
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    expected void **slot
drivers/gpu/drm/i915/gvt/gtt.c:757:9:    got void [noderef] <asn:4> **

This would also have been loudly warning if run through CI for the
invalid RCU dereferences.

Fixes: b6c126a393 ("drm/i915/gvt: Manage shadow pages with radix tree")
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
2019-04-08 10:39:52 +08:00
2019-03-07 18:32:03 -08:00
2019-02-21 11:41:19 +00:00
2019-03-17 14:22:26 -07:00

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.
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