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Mathias Krause 2b562f032f drm/i915: Register engines early to avoid type confusion
Commit 1ec23ed712 ("drm/i915: Use uabi engines for the default engine
map") switched from using for_each_engine() to for_each_uabi_engine() to
iterate over the user engines. While this seems to be a sensible change,
it's only safe to do when the engines are actually chained using the
rb-tree structure which is not the case during early driver
initialization where it can be either a lock-less list or regular
double-linked list.

In fact, the modesetting initialization code may end up calling
default_engines() through the fb helper code while the engines list
is still llist_node-based:

  i915_driver_probe() ->
    intel_display_driver_probe() ->
      intel_fbdev_init() ->
        drm_fb_helper_init() ->
          drm_client_init() ->
            drm_client_open() ->
              drm_file_alloc() ->
                i915_driver_open() ->
                  i915_gem_open() ->
                    i915_gem_context_open() ->
                      i915_gem_create_context() ->
                        default_engines()

Using for_each_uabi_engine() in default_engines() is therefore wrong, as
it would try to interpret the llist as rb-tree, making it find no engine
at all, as the rb_left and rb_right members will still be NULL, as they
haven't been initialized yet.

To fix this type confusion register the engines earlier and at the same
time reduce the amount of code that has to deal with the intermediate
llist state.

Reported-by: sanity checks in grsecurity
Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 1ec23ed712 ("drm/i915: Use uabi engines for the default engine map")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230928182019.10256-2-minipli@grsecurity.net
[tursulin: fixed commit tag typo]
2023-10-03 08:30:52 +01:00
arch sh: mach-sh7763rdp: Assign FB_MODE_IS_UNKNOWN to struct fb_videomode.flag 2023-07-24 16:50:38 +02:00
block SCSI fixes on 20230714 2023-07-14 19:57:29 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: algif_hash - Fix race between MORE and non-MORE sends 2023-07-08 22:48:42 +10:00
Documentation - Removing unused declarations (Arnd, Gustavo) 2023-08-07 13:47:30 +10:00
drivers drm/i915: Register engines early to avoid type confusion 2023-10-03 08:30:52 +01:00
fs Five smb3 client fixes 2023-07-16 12:49:05 -07:00
include drm/i915/mtl: Adding DeviceID for Arrowlake-S under MTL 2023-08-23 08:07:39 -07:00
init Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring io_uring-6.5-2023-07-14 2023-07-14 19:46:54 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel - Remove a cgroup from under a polling process properly 2023-07-16 13:22:08 -07:00
lib iov_iter: Mark copy_iovec_from_user() noclone 2023-07-10 09:52:28 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: lock newly mapped VMA with corrected ordering 2023-07-08 16:44:11 -07:00
net A fix to prevent a potential buffer overrun in the messenger, marked 2023-07-14 09:05:15 -07:00
rust rust: error: impl Debug for Error with errname() integration 2023-06-13 01:24:42 +02:00
samples vfio-mdev: Remove flag FBINFO_DEFAULT from fbdev sample driver 2023-07-24 16:50:38 +02:00
scripts kallsyms: strip LTO-only suffixes from promoted global functions 2023-07-12 15:39:34 -07:00
security + Bug Fixes 2023-07-07 09:55:31 -07:00
sound sound fixes for 6.5-rc1 2023-07-07 15:40:17 -07:00
tools - Mark copy_iovec_from_user() __noclone in order to prevent gcc from 2023-07-16 13:34:29 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM64: 2023-07-03 15:32:22 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap spi: Fixes for v6.5 2023-07-15 08:51:02 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS drm-misc-next for v6.6: 2023-07-17 15:37:57 +02:00
Makefile Linux 6.5-rc2 2023-07-16 15:10:37 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.