<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/drivers/gpu/drm/drm_ioctl.c, branch v5.10.257</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.257</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.257'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2022-10-26T11:25:48+00:00</updated>
<entry>
<title>drm: Prevent drm_copy_field() to attempt copying a NULL pointer</title>
<updated>2022-10-26T11:25:48+00:00</updated>
<author>
<name>Javier Martinez Canillas</name>
<email>javierm@redhat.com</email>
</author>
<published>2022-07-05T10:02:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c28a8082b25ce4ec94999e10a30c50d20bd44a25'/>
<id>urn:sha1:c28a8082b25ce4ec94999e10a30c50d20bd44a25</id>
<content type='text'>
[ Upstream commit f6ee30407e883042482ad4ad30da5eaba47872ee ]

There are some struct drm_driver fields that are required by drivers since
drm_copy_field() attempts to copy them to user-space via DRM_IOCTL_VERSION.

But it can be possible that a driver has a bug and did not set some of the
fields, which leads to drm_copy_field() attempting to copy a NULL pointer:

[ +10.395966] Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000
[  +0.010955] Mem abort info:
[  +0.002835]   ESR = 0x0000000096000004
[  +0.003872]   EC = 0x25: DABT (current EL), IL = 32 bits
[  +0.005395]   SET = 0, FnV = 0
[  +0.003113]   EA = 0, S1PTW = 0
[  +0.003182]   FSC = 0x04: level 0 translation fault
[  +0.004964] Data abort info:
[  +0.002919]   ISV = 0, ISS = 0x00000004
[  +0.003886]   CM = 0, WnR = 0
[  +0.003040] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000115dad000
[  +0.006536] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[  +0.006925] Internal error: Oops: 96000004 [#1] SMP
...
[  +0.011113] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  +0.007061] pc : __pi_strlen+0x14/0x150
[  +0.003895] lr : drm_copy_field+0x30/0x1a4
[  +0.004156] sp : ffff8000094b3a50
[  +0.003355] x29: ffff8000094b3a50 x28: ffff8000094b3b70 x27: 0000000000000040
[  +0.007242] x26: ffff443743c2ba00 x25: 0000000000000000 x24: 0000000000000040
[  +0.007243] x23: ffff443743c2ba00 x22: ffff8000094b3b70 x21: 0000000000000000
[  +0.007241] x20: 0000000000000000 x19: ffff8000094b3b90 x18: 0000000000000000
[  +0.007241] x17: 0000000000000000 x16: 0000000000000000 x15: 0000aaab14b9af40
[  +0.007241] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[  +0.007239] x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa524ad67d4d8
[  +0.007242] x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : 6c6e6263606e7141
[  +0.007239] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
[  +0.007241] x2 : 0000000000000000 x1 : ffff8000094b3b90 x0 : 0000000000000000
[  +0.007240] Call trace:
[  +0.002475]  __pi_strlen+0x14/0x150
[  +0.003537]  drm_version+0x84/0xac
[  +0.003448]  drm_ioctl_kernel+0xa8/0x16c
[  +0.003975]  drm_ioctl+0x270/0x580
[  +0.003448]  __arm64_sys_ioctl+0xb8/0xfc
[  +0.003978]  invoke_syscall+0x78/0x100
[  +0.003799]  el0_svc_common.constprop.0+0x4c/0xf4
[  +0.004767]  do_el0_svc+0x38/0x4c
[  +0.003357]  el0_svc+0x34/0x100
[  +0.003185]  el0t_64_sync_handler+0x11c/0x150
[  +0.004418]  el0t_64_sync+0x190/0x194
[  +0.003716] Code: 92402c04 b200c3e8 f13fc09f 5400088c (a9400c02)
[  +0.006180] ---[ end trace 0000000000000000 ]---

Reported-by: Peter Robinson &lt;pbrobinson@gmail.com&gt;
Signed-off-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Acked-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220705100215.572498-3-javierm@redhat.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>drm: Use size_t type for len variable in drm_copy_field()</title>
<updated>2022-10-26T11:25:48+00:00</updated>
<author>
<name>Javier Martinez Canillas</name>
<email>javierm@redhat.com</email>
</author>
<published>2022-07-05T10:02:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e7d701800365d2dd3ef2252497dcaed9a2d2fada'/>
<id>urn:sha1:e7d701800365d2dd3ef2252497dcaed9a2d2fada</id>
<content type='text'>
[ Upstream commit 94dc3471d1b2b58b3728558d0e3f264e9ce6ff59 ]

The strlen() function returns a size_t which is an unsigned int on 32-bit
arches and an unsigned long on 64-bit arches. But in the drm_copy_field()
function, the strlen() return value is assigned to an 'int len' variable.

Later, the len variable is passed as copy_from_user() third argument that
is an unsigned long parameter as well.

In theory, this can lead to an integer overflow via type conversion. Since
the assignment happens to a signed int lvalue instead of a size_t lvalue.

In practice though, that's unlikely since the values copied are set by DRM
drivers and not controlled by userspace. But using a size_t for len is the
correct thing to do anyways.

Signed-off-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Tested-by: Peter Robinson &lt;pbrobinson@gmail.com&gt;
Reviewed-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220705100215.572498-2-javierm@redhat.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>drm: Return -ENOTTY for non-drm ioctls</title>
<updated>2021-07-28T12:35:47+00:00</updated>
<author>
<name>Charles Baylis</name>
<email>cb-kernel@fishzet.co.uk</email>
</author>
<published>2021-07-16T16:43:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=69a603aa170e1c145b93d5d7efcca83a8b1268fe'/>
<id>urn:sha1:69a603aa170e1c145b93d5d7efcca83a8b1268fe</id>
<content type='text'>
commit 3abab27c322e0f2acf981595aa8040c9164dc9fb upstream.

drm: Return -ENOTTY for non-drm ioctls

Return -ENOTTY from drm_ioctl() when userspace passes in a cmd number
which doesn't relate to the drm subsystem.

Glibc uses the TCGETS ioctl to implement isatty(), and without this
change isatty() returns it incorrectly returns true for drm devices.

To test run this command:
$ if [ -t 0 ]; then echo is a tty; fi &lt; /dev/dri/card0
which shows "is a tty" without this patch.

This may also modify memory which the userspace application is not
expecting.

Signed-off-by: Charles Baylis &lt;cb-kernel@fishzet.co.uk&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/YPG3IBlzaMhfPqCr@stando.fishzet.co.uk
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>drm: Fix use-after-free read in drm_getunique()</title>
<updated>2021-06-16T10:01:39+00:00</updated>
<author>
<name>Desmond Cheong Zhi Xi</name>
<email>desmondcheongzx@gmail.com</email>
</author>
<published>2021-06-08T11:04:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=491d52e0078860b33b6c14f0a7ac74ca1b603bd6'/>
<id>urn:sha1:491d52e0078860b33b6c14f0a7ac74ca1b603bd6</id>
<content type='text'>
commit b436acd1cf7fac0ba987abd22955d98025c80c2b upstream.

There is a time-of-check-to-time-of-use error in drm_getunique() due
to retrieving file_priv-&gt;master prior to locking the device's master
mutex.

An example can be seen in the crash report of the use-after-free error
found by Syzbot:
https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803

In the report, the master pointer was used after being freed. This is
because another process had acquired the device's master mutex in
drm_setmaster_ioctl(), then overwrote fpriv-&gt;master in
drm_new_set_master(). The old value of fpriv-&gt;master was subsequently
freed before the mutex was unlocked.

To fix this, we lock the device's master mutex before retrieving the
pointer from from fpriv-&gt;master. This patch passes the Syzbot
reproducer test.

Reported-by: syzbot+c3a706cec1ea99e1c693@syzkaller.appspotmail.com
Signed-off-by: Desmond Cheong Zhi Xi &lt;desmondcheongzx@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20210608110436.239583-1-desmondcheongzx@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'drm-misc-next-2020-06-19' of git://anongit.freedesktop.org/drm/drm-misc into drm-next</title>
<updated>2020-06-24T05:45:51+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2020-06-23T00:58:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=0a19b068acc47d05212f03e494381926dc0381e2'/>
<id>urn:sha1:0a19b068acc47d05212f03e494381926dc0381e2</id>
<content type='text'>
drm-misc-next for v5.9:

UAPI Changes:
- Add DRM_MODE_TYPE_USERDEF for video modes specified in cmdline.

Cross-subsystem Changes:
- Assorted devicetree binding updates.
- Add might_sleep() to dma_fence_wait().
- Fix fbdev's get_user_pages_fast() handling, and use pin_user_pages.
- Small cleanup with IS_BUILTIN in video/fbdev drivers.
- Fix video/hdmi coding style for infoframe size.

Core Changes:
- Silence vblank output during init.
- Fix DP-MST corruption during send msg timeout.
- Clear leak in drm_gem_objecs_lookup().
- Make newlines work with force connector attribute.
- Fix module refcounting error in drm_encoder_slave, and use new i2c api.
- Header fix for drm_managed.c
- More struct_mutex removal for !legacy drivers:
  - Remove gem_free_object()
  - Removal of drm_gem_object_put_unlocked().
- Show current-&gt;comm alongside pid in debug printfs.
- Add drm_client_modeset_check() + drm_client_framebuffer_flush().
- Replace drm_fb_swab16 with drm_fb_swap that also supports 32-bits.
- Remove mode-&gt;vrefresh, and compactify drm_display_mode.
- Use drm_* macros for logging and warnings.
- Add WARN when drm_gem_get_pages is used on a private obj.
- Handle importing and imported dmabuf better in shmem helpers.
- Small fix for drm/mm hole size comparison, and remove invalid entry optimization.
- Add a drm/mm selftest.
- Set DSI connector type for DSI panels.
- Assorted small fixes and documentation updates.
- Fix DDI I2C device registration for MST ports, and flushing on destroy.
- Fix master_set return type, used by vmwgfx.
- Make the drm_set/drop_master ioctl symmetrical.

Driver Changes:
 Allow iommu in the sun4i driver and use it for sun8i.
- Simplify backlight lookup for omap, amba-clcd and tilcdc.
- Hold reg_lock for rockchip.
- Add support for bridge gpio and lane reordering + polarity to ti-sn65dsi86, and fix clock choice.
- Small assorted fixes to tilcdc, vc4, i915, omap, fbdev/sm712fb, fbdev/pxafb, console/newport_con, msm, virtio, udl, malidp, hdlcd, bridge/ti-sn65dsi86, panfrost.
- Remove hw cursor support for mgag200, and use simple kms helper + shmem helpers.
- Add support for KOE  Allow iommu in the sun4i driver and use it for sun8i.
- Simplify backlight lookup for omap, amba-clcd and tilcdc.
- Hold reg_lock for rockchip.
- Add support for bridge gpio and lane reordering + polarity to ti-sn65dsi86, and fix clock choice.
- Small assorted fixes to tilcdc, vc4 (multiple), i915.
- Remove hw cursor support for mgag200, and use simple kms helper + shmem helpers.
- Add support for KOE TX26D202VM0BWA panel.
- Use GEM CMA functions in arc, arm, atmel-hlcdc, fsi-dcu, hisilicon, imx, ingenic, komeda, malidp, mcde, meson, msxfb, rcar-du, shmobile, stm, sti, tilcdc, tve200, zte.
- Remove gem_print_info.
- Improve gem_create_object_helper so udl can use shmem helpers.
- Convert vc4 dt bindings to schemas, and add clock properties.
- Device initialization cleanups for mgag200.
- Add a workaround to fix DP-MST short pulses handling on broken hardware in i915.
- Allow build test compiling arm drivers.
- Use managed pci functions in mgag200 and ast.
- Use dev_groups in malidp.
- Add per pixel alpha support for PX30 VOP in rockchip.
- Silence deferred probe logs in panfrost.

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;

From: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/001cd9a6-405d-4e29-43d8-354f53ae4e8b@linux.intel.com
</content>
</entry>
<entry>
<title>Merge tag 'drm-next-2020-06-02' of git://anongit.freedesktop.org/drm/drm</title>
<updated>2020-06-02T22:04:15+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-06-02T22:04:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=faa392181a0bd42c5478175cef601adeecdc91b6'/>
<id>urn:sha1:faa392181a0bd42c5478175cef601adeecdc91b6</id>
<content type='text'>
Pull drm updates from Dave Airlie:
 "Highlights:

   - Core DRM had a lot of refactoring around managed drm resources to
     make drivers simpler.

   - Intel Tigerlake support is on by default

   - amdgpu now support p2p PCI buffer sharing and encrypted GPU memory

  Details:

  core:
   - uapi: error out EBUSY when existing master
   - uapi: rework SET/DROP MASTER permission handling
   - remove drm_pci.h
   - drm_pci* are now legacy
   - introduced managed DRM resources
   - subclassing support for drm_framebuffer
   - simple encoder helper
   - edid improvements
   - vblank + writeback documentation improved
   - drm/mm - optimise tree searches
   - port drivers to use devm_drm_dev_alloc

  dma-buf:
   - add flag for p2p buffer support

  mst:
   - ACT timeout improvements
   - remove drm_dp_mst_has_audio
   - don't use 2nd TX slot - spec recommends against it

  bridge:
   - dw-hdmi various improvements
   - chrontel ch7033 support
   - fix stack issues with old gcc

  hdmi:
   - add unpack function for drm infoframe

  fbdev:
   - misc fbdev driver fixes

  i915:
   - uapi: global sseu pinning
   - uapi: OA buffer polling
   - uapi: remove generated perf code
   - uapi: per-engine default property values in sysfs
   - Tigerlake GEN12 enabled.
   - Lots of gem refactoring
   - Tigerlake enablement patches
   - move to drm_device logging
   - Icelake gamma HW readout
   - push MST link retrain to hotplug work
   - bandwidth atomic helpers
   - ICL fixes
   - RPS/GT refactoring
   - Cherryview full-ppgtt support
   - i915 locking guidelines documented
   - require linear fb stride to be 512 multiple on gen9
   - Tigerlake SAGV support

  amdgpu:
   - uapi: encrypted GPU memory handling
   - uapi: add MEM_SYNC IB flag
   - p2p dma-buf support
   - export VRAM dma-bufs
   - FRU chip access support
   - RAS/SR-IOV updates
   - Powerplay locking fixes
   - VCN DPG (powergating) enablement
   - GFX10 clockgating fixes
   - DC fixes
   - GPU reset fixes
   - navi SDMA fix
   - expose FP16 for modesetting
   - DP 1.4 compliance fixes
   - gfx10 soft recovery
   - Improved Critical Thermal Faults handling
   - resizable BAR on gmc10

  amdkfd:
   - uapi: GWS resource management
   - track GPU memory per process
   - report PCI domain in topology

  radeon:
   - safe reg list generator fixes

  nouveau:
   - HD audio fixes on recent systems
   - vGPU detection (fail probe if we're on one, for now)
   - Interlaced mode fixes (mostly avoidance on Turing, which doesn't support it)
   - SVM improvements/fixes
   - NVIDIA format modifier support
   - Misc other fixes.

  adv7511:
   - HDMI SPDIF support

  ast:
   - allocate crtc state size
   - fix double assignment
   - fix suspend

  bochs:
   - drop connector register

  cirrus:
   - move to tiny drivers.

  exynos:
   - fix imported dma-buf mapping
   - enable runtime PM
   - fixes and cleanups

  mediatek:
   - DPI pin mode swap
   - config mipi_tx current/impedance

  lima:
   - devfreq + cooling device support
   - task handling improvements
   - runtime PM support

  pl111:
   - vexpress init improvements
   - fix module auto-load

  rcar-du:
   - DT bindings conversion to YAML
   - Planes zpos sanity check and fix
   - MAINTAINERS entry for LVDS panel driver

  mcde:
   - fix return value

  mgag200:
   - use managed config init

  stm:
   - read endpoints from DT

  vboxvideo:
   - use PCI managed functions
   - drop WC mtrr

  vkms:
   - enable cursor by default

  rockchip:
   - afbc support

  virtio:
   - various cleanups

  qxl:
   - fix cursor notify port

  hisilicon:
   - 128-byte stride alignment fix

  sun4i:
   - improved format handling"

* tag 'drm-next-2020-06-02' of git://anongit.freedesktop.org/drm/drm: (1401 commits)
  drm/amd/display: Fix potential integer wraparound resulting in a hang
  drm/amd/display: drop cursor position check in atomic test
  drm/amdgpu: fix device attribute node create failed with multi gpu
  drm/nouveau: use correct conflicting framebuffer API
  drm/vblank: Fix -Wformat compile warnings on some arches
  drm/amdgpu: Sync with VM root BO when switching VM to CPU update mode
  drm/amd/display: Handle GPU reset for DC block
  drm/amdgpu: add apu flags (v2)
  drm/amd/powerpay: Disable gfxoff when setting manual mode on picasso and raven
  drm/amdgpu: fix pm sysfs node handling (v2)
  drm/amdgpu: move gpu_info parsing after common early init
  drm/amdgpu: move discovery gfx config fetching
  drm/nouveau/dispnv50: fix runtime pm imbalance on error
  drm/nouveau: fix runtime pm imbalance on error
  drm/nouveau: fix runtime pm imbalance on error
  drm/nouveau/debugfs: fix runtime pm imbalance on error
  drm/nouveau/nouveau/hmm: fix migrate zero page to GPU
  drm/nouveau/nouveau/hmm: fix nouveau_dmem_chunk allocations
  drm/nouveau/kms/nv50-: Share DP SST mode_valid() handling with MST
  drm/nouveau/kms/nv50-: Move 8BPC limit for MST into nv50_mstc_get_modes()
  ...
</content>
</entry>
<entry>
<title>drm: print the current-&gt;comm alongside the pid</title>
<updated>2020-05-19T21:31:37+00:00</updated>
<author>
<name>Emil Velikov</name>
<email>emil.velikov@collabora.com</email>
</author>
<published>2020-05-18T08:33:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5a2ba99222fc2897311ed48745562952b8f030ad'/>
<id>urn:sha1:5a2ba99222fc2897311ed48745562952b8f030ad</id>
<content type='text'>
The question of "what process is this pid" keeps on popping up, so lets
print the process name alongside the pid.

Cc: Mauro Rossi &lt;issor.oruam@gmail.com&gt;
Cc: Bob Beckett &lt;bob.beckett@collabora.com&gt;
Cc: Pekka Paalanen &lt;pekka.paalanen@collabora.co.uk&gt;
Signed-off-by: Emil Velikov &lt;emil.velikov@collabora.com&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200518083315.129948-1-emil.l.velikov@gmail.com
</content>
</entry>
<entry>
<title>docs: fix broken references to text files</title>
<updated>2020-04-20T21:35:59+00:00</updated>
<author>
<name>Mauro Carvalho Chehab</name>
<email>mchehab+huawei@kernel.org</email>
</author>
<published>2020-04-14T16:48:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=72ef5e52b3f74c0be47b20f5c434b7ecc830cf40'/>
<id>urn:sha1:72ef5e52b3f74c0be47b20f5c434b7ecc830cf40</id>
<content type='text'>
Several references got broken due to txt to ReST conversion.

Several of them can be automatically fixed with:

	scripts/documentation-file-ref-check --fix

Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt; # hwtracing/coresight/Kconfig
Reviewed-by: Paul E. McKenney &lt;paulmck@kernel.org&gt; # memory-barrier.txt
Acked-by: Alex Shi &lt;alex.shi@linux.alibaba.com&gt; # translations/zh_CN
Acked-by: Federico Vaga &lt;federico.vaga@vaga.pv.it&gt; # translations/it_IT
Acked-by: Marc Zyngier &lt;maz@kernel.org&gt; # kvm/arm64
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
</entry>
<entry>
<title>drm: rework SET_MASTER and DROP_MASTER perm handling</title>
<updated>2020-03-30T11:20:32+00:00</updated>
<author>
<name>Emil Velikov</name>
<email>emil.velikov@collabora.com</email>
</author>
<published>2020-03-19T17:29:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=45bc3d26c95a8fc63a7d8668ca9e57ef0883351c'/>
<id>urn:sha1:45bc3d26c95a8fc63a7d8668ca9e57ef0883351c</id>
<content type='text'>
This commit reworks the permission handling of the two ioctls. In
particular it enforced the CAP_SYS_ADMIN check only, if:
 - we're issuing the ioctl from process other than the one which opened
the node, and
 - we are, or were master in the past

This ensures that we:
 - do not regress the systemd-logind style of DRM_MASTER arbitrator
 - allow applications which do not use systemd-logind to drop their
master capabilities (and regain them at later point) ... w/o running as
root.

See the comment above drm_master_check_perm() for more details.

v1:
 - Tweak wording, fixup all checks, add igt test

v2:
 - Add a few more comments, grammar nitpicks.

Cc: Adam Jackson &lt;ajax@redhat.com&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Pekka Paalanen &lt;ppaalanen@gmail.com&gt;
Testcase: igt/core_setmaster/master-drop-set-user
Signed-off-by: Emil Velikov &lt;emil.velikov@collabora.com&gt;
Reviewed-by: Adam Jackson &lt;ajax@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200319172930.230583-1-emil.l.velikov@gmail.com
</content>
</entry>
<entry>
<title>drm: Add getfb2 ioctl</title>
<updated>2020-01-14T21:22:17+00:00</updated>
<author>
<name>Daniel Stone</name>
<email>daniels@collabora.com</email>
</author>
<published>2019-12-17T03:46:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=455e00f1412fe51fa7bd21ad6fe0015b163fa9e5'/>
<id>urn:sha1:455e00f1412fe51fa7bd21ad6fe0015b163fa9e5</id>
<content type='text'>
getfb2 allows us to pass multiple planes and modifiers, just like addfb2
over addfb.

Changes since v2:
 - add privilege checks from getfb1 since handles should only be
   returned to master/root

Changes since v1:
 - unused modifiers set to 0 instead of DRM_FORMAT_MOD_INVALID
 - update ioctl number

Signed-off-by: Daniel Stone &lt;daniels@collabora.com&gt;
Signed-off-by: Juston Li &lt;juston.li@intel.com&gt;
Acked-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20191217034642.3814-1-juston.li@intel.com
</content>
</entry>
</feed>
