linux-stable.git/drivers/gpu/drm, branch v5.4.47

drm/vkms: Hold gem object while still in-use

2020-06-17T14:40:36+00:00

commit 0ea2ea42b31abc1141f2fd3911f952a97d401fcb upstream.

We need to keep the reference to the drm_gem_object
until the last access by vkms_dumb_create.

Therefore, the put the object after it is used.

This fixes a use-after-free issue reported by syzbot.

While here, change vkms_gem_create() symbol to static.

Reported-and-tested-by: syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com
Signed-off-by: Ezequiel Garcia 
Reviewed-by: Rodrigo Siqueira 
Signed-off-by: Rodrigo Siqueira 
Link: https://patchwork.freedesktop.org/patch/msgid/20200427214405.13069-1-ezequiel@collabora.com
Signed-off-by: Greg Kroah-Hartman

gup: document and work around "COW can break either way" issue

2020-06-17T14:40:30+00:00

commit 17839856fd588f4ab6b789f482ed3ffd7c403e1f upstream.

Doing a "get_user_pages()" on a copy-on-write page for reading can be
ambiguous: the page can be COW'ed at any time afterwards, and the
direction of a COW event isn't defined.

Yes, whoever writes to it will generally do the COW, but if the thread
that did the get_user_pages() unmapped the page before the write (and
that could happen due to memory pressure in addition to any outright
action), the writer could also just take over the old page instead.

End result: the get_user_pages() call might result in a page pointer
that is no longer associated with the original VM, and is associated
with - and controlled by - another VM having taken it over instead.

So when doing a get_user_pages() on a COW mapping, the only really safe
thing to do would be to break the COW when getting the page, even when
only getting it for reading.

At the same time, some users simply don't even care.

For example, the perf code wants to look up the page not because it
cares about the page, but because the code simply wants to look up the
physical address of the access for informational purposes, and doesn't
really care about races when a page might be unmapped and remapped
elsewhere.

This adds logic to force a COW event by setting FOLL_WRITE on any
copy-on-write mapping when FOLL_GET (or FOLL_PIN) is used to get a page
pointer as a result.

The current semantics end up being:

 - __get_user_pages_fast(): no change. If you don't ask for a write,
   you won't break COW. You'd better know what you're doing.

 - get_user_pages_fast(): the fast-case "look it up in the page tables
   without anything getting mmap_sem" now refuses to follow a read-only
   page, since it might need COW breaking.  Which happens in the slow
   path - the fast path doesn't know if the memory might be COW or not.

 - get_user_pages() (including the slow-path fallback for gup_fast()):
   for a COW mapping, turn on FOLL_WRITE for FOLL_GET/FOLL_PIN, with
   very similar semantics to FOLL_FORCE.

If it turns out that we want finer granularity (ie "only break COW when
it might actually matter" - things like the zero page are special and
don't need to be broken) we might need to push these semantics deeper
into the lookup fault path.  So if people care enough, it's possible
that we might end up adding a new internal FOLL_BREAK_COW flag to go
with the internal FOLL_COW flag we already have for tracking "I had a
COW".

Alternatively, if it turns out that different callers might want to
explicitly control the forced COW break behavior, we might even want to
make such a flag visible to the users of get_user_pages() instead of
using the above default semantics.

But for now, this is mostly commentary on the issue (this commit message
being a lot bigger than the patch, and that patch in turn is almost all
comments), with that minimal "enable COW breaking early" logic using the
existing FOLL_WRITE behavior.

[ It might be worth noting that we've always had this ambiguity, and it
  could arguably be seen as a user-space issue.

  You only get private COW mappings that could break either way in
  situations where user space is doing cooperative things (ie fork()
  before an execve() etc), but it _is_ surprising and very subtle, and
  fork() is supposed to give you independent address spaces.

  So let's treat this as a kernel issue and make the semantics of
  get_user_pages() easier to understand. Note that obviously a true
  shared mapping will still get a page that can change under us, so this
  does _not_ mean that get_user_pages() somehow returns any "stable"
  page ]

Reported-by: Jann Horn 
Tested-by: Christoph Hellwig 
Acked-by: Oleg Nesterov 
Acked-by: Kirill Shutemov 
Acked-by: Jan Kara 
Cc: Andrea Arcangeli 
Cc: Matthew Wilcox 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

drm/edid: Add Oculus Rift S to non-desktop list

2020-06-07T11:18:51+00:00

[ Upstream commit 5a3f610877e9d08968ea7237551049581f02b163 ]

Add a quirk for the Oculus Rift S OVR0012 display so
it shows up as a non-desktop display.

Signed-off-by: Jan Schmidt 
Signed-off-by: Dave Airlie 
Link: https://patchwork.freedesktop.org/patch/msgid/20200507180628.740936-1-jan@centricular.com
Signed-off-by: Sasha Levin

drm/i915: fix port checks for MST support on gen >= 11

2020-06-07T11:18:48+00:00

[ Upstream commit 10d987fd1b7baceaafa78d805e71427ab735b4e4 ]

Both Ice Lake and Elkhart Lake (gen 11) support MST on all external
connections except DDI A. Tiger Lake (gen 12) supports on all external
connections.

Move the check to happen inside intel_dp_mst_encoder_init() and add
specific platform checks.

v2: Replace != with == checks for ports on gen < 11 (Ville)

Signed-off-by: Lucas De Marchi 
Reviewed-by: Ville Syrjälä 
Link: https://patchwork.freedesktop.org/patch/msgid/20191015164029.18431-3-lucas.demarchi@intel.com
Signed-off-by: Sasha Levin

drm/amd/display: drop cursor position check in atomic test

2020-06-03T06:21:25+00:00

[ Upstream commit f7d5991b92ff824798693ddf231cf814c9d5a88b ]

get_cursor_position already handles the case where the cursor has
negative off-screen coordinates by not setting
dc_cursor_position.enabled.

Signed-off-by: Simon Ser 
Fixes: 626bf90fe03f ("drm/amd/display: add basic atomic check for cursor plane")
Cc: Alex Deucher 
Cc: Nicholas Kazlauskas 
Signed-off-by: Alex Deucher 
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin

gpu/drm: Ingenic: Fix opaque pointer casted to wrong type

2020-06-03T06:21:19+00:00

[ Upstream commit abf56fadf0e208abfb13ad1ac0094416058da0ad ]

The opaque pointer passed to the IRQ handler is a pointer to the
drm_device, not a pointer to our ingenic_drm structure.

It still worked, because our ingenic_drm structure contains the
drm_device as its first field, so the pointer received had the same
value, but this was not semantically correct.

Cc: stable@vger.kernel.org # v5.3
Fixes: 90b86fcc47b4 ("DRM: Add KMS driver for the Ingenic JZ47xx SoCs")
Signed-off-by: Paul Cercueil 
Link: https://patchwork.freedesktop.org/patch/msgid/20200516215057.392609-5-paul@crapouillou.net
Acked-by: Sam Ravnborg 
Signed-off-by: Sasha Levin

drm/amdgpu: Use GEM obj reference for KFD BOs

2020-06-03T06:21:11+00:00

[ Upstream commit 39b3128d7ffd44e400e581e6f49e88cb42bef9a1 ]

Releasing the AMDGPU BO ref directly leads to problems when BOs were
exported as DMA bufs. Releasing the GEM reference makes sure that the
AMDGPU/TTM BO is not freed too early.

Also take a GEM reference when importing BOs from DMABufs to keep
references to imported BOs balances properly.

Signed-off-by: Felix Kuehling 
Tested-by: Alex Sierra 
Acked-by: Christian König 
Reviewed-by: Alex Sierra 
Signed-off-by: Alex Deucher 
Signed-off-by: Sasha Levin

drm/amd/powerplay: perform PG ungate prior to CG ungate

2020-06-03T06:21:10+00:00

[ Upstream commit f4fcfa4282c1a1bf51475ebb0ffda623eebf1191 ]

Since gfxoff should be disabled first before trying to access those
GC registers.

Signed-off-by: Evan Quan 
Reviewed-by: Alex Deucher 
Signed-off-by: Alex Deucher 
Signed-off-by: Sasha Levin

drm/amdgpu: drop unnecessary cancel_delayed_work_sync on PG ungate

2020-06-03T06:21:10+00:00

[ Upstream commit 1fe48ec08d9f2e26d893a6c05bd6c99a3490f9ef ]

As this is already properly handled in amdgpu_gfx_off_ctrl(). In fact,
this unnecessary cancel_delayed_work_sync may leave a small time window
for race condition and is dangerous.

Signed-off-by: Evan Quan 
Reviewed-by: Alex Deucher 
Signed-off-by: Alex Deucher 
Signed-off-by: Sasha Levin

drm/i915: Propagate error from completed fences

2020-05-27T15:46:43+00:00

commit bc850943486887e3859597a266767f95db90aa72 upstream.

We need to preserve fatal errors from fences that are being terminated
as we hook them up.

Fixes: ef4688497512 ("drm/i915: Propagate fence errors")
Signed-off-by: Chris Wilson 
Cc: Tvrtko Ursulin 
Cc: Matthew Auld 
Reviewed-by: Matthew Auld 
Link: https://patchwork.freedesktop.org/patch/msgid/20200506162136.3325-1-chris@chris-wilson.co.uk
(cherry picked from commit 24fe5f2ab2478053d50a3bc629ada895903a5cbc)
Signed-off-by: Rodrigo Vivi 
Signed-off-by: Greg Kroah-Hartman