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  1. Oct 19, 2018
    • Boris Brezillon's avatar
      drm/sun4i: Fix an ulong overflow in the dotclock driver · e84cb605
      Boris Brezillon authored 
      

The calculated ideal rate can easily overflow an unsigned long, thus
making the best div selection buggy as soon as no ideal match is found
before the overflow occurs.

Fixes: 4731a72d ("drm/sun4i: request exact rates to our parents")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
Acked-by: default avatarMaxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181018100250.12565-1-boris.brezillon@bootlin.com
      e84cb605
    • Leo Li's avatar
      drm: Get ref on CRTC commit object when waiting for flip_done · 4364bcb2
      Leo Li authored 
      

This fixes a general protection fault, caused by accessing the contents
of a flip_done completion object that has already been freed. It occurs
due to the preemption of a non-blocking commit worker thread W by
another commit thread X. X continues to clear its atomic state at the
end, destroying the CRTC commit object that W still needs. Switching
back to W and accessing the commit objects then leads to bad results.

Worker W becomes preemptable when waiting for flip_done to complete. At
this point, a frequently occurring commit thread X can take over. Here's
an example where W is a worker thread that flips on both CRTCs, and X
does a legacy cursor update on both CRTCs:

        ...
     1. W does flip work
     2. W runs commit_hw_done()
     3. W waits for flip_done on CRTC 1
     4. > flip_done for CRTC 1 completes
     5. W finishes waiting for CRTC 1
     6. W waits for flip_done on CRTC 2

     7. > Preempted by X
     8. > flip_done for CRTC 2 completes
     9. X atomic_check: hw_done and flip_done are complete on all CRTCs
    10. X updates cursor on both CRTCs
    11. X destroys atomic state
    12. X done

    13. > Switch back to W
    14. W waits for flip_done on CRTC 2
    15. W raises general protection fault

The error looks like so:

    general protection fault: 0000 [#1] PREEMPT SMP PTI
    **snip**
    Call Trace:
     lock_acquire+0xa2/0x1b0
     _raw_spin_lock_irq+0x39/0x70
     wait_for_completion_timeout+0x31/0x130
     drm_atomic_helper_wait_for_flip_done+0x64/0x90 [drm_kms_helper]
     amdgpu_dm_atomic_commit_tail+0xcae/0xdd0 [amdgpu]
     commit_tail+0x3d/0x70 [drm_kms_helper]
     process_one_work+0x212/0x650
     worker_thread+0x49/0x420
     kthread+0xfb/0x130
     ret_from_fork+0x3a/0x50
    Modules linked in: x86_pkg_temp_thermal amdgpu(O) chash(O)
    gpu_sched(O) drm_kms_helper(O) syscopyarea sysfillrect sysimgblt
    fb_sys_fops ttm(O) drm(O)

Note that i915 has this issue masked, since hw_done is signaled after
waiting for flip_done. Doing so will block the cursor update from
happening until hw_done is signaled, preventing the cursor commit from
destroying the state.

v2: The reference on the commit object needs to be obtained before
    hw_done() is signaled, since that's the point where another commit
    is allowed to modify the state. Assuming that the
    new_crtc_state->commit object still exists within flip_done() is
    incorrect.

    Fix by getting a reference in setup_commit(), and releasing it
    during default_clear().

Signed-off-by: default avatarLeo Li <sunpeng.li@amd.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarHarry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1539611200-6184-1-git-send-email-sunpeng.li@amd.com
      4364bcb2
  3. Oct 16, 2018
  5. Oct 05, 2018
  7. Oct 04, 2018
  9. Oct 03, 2018
  11. Oct 02, 2018
    • Noralf Trønnes's avatar
      drm/cma-helper: Fix crash in fbdev error path · 4d4c2d89
      Noralf Trønnes authored 
      

Sergey Suloev reported a crash happening in drm_client_dev_hotplug()
when fbdev had failed to register.

[    9.124598] vc4_hdmi 3f902000.hdmi: ASoC: Failed to create component debugfs directory
[    9.147667] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi mapping ok
[    9.155184] vc4_hdmi 3f902000.hdmi: ASoC: no DMI vendor name!
[    9.166544] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[    9.173840] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4])
[    9.181029] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
[    9.188519] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[    9.195690] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[    9.203523] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[    9.215032] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[    9.274785] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
[    9.290246] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
[    9.297464] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    9.304600] [drm] Driver supports precise vblank timestamp query.
[    9.382856] vc4-drm soc:gpu: [drm:drm_fb_helper_fbdev_setup [drm_kms_helper]] *ERROR* Failed to set fbdev configuration
[   10.404937] Unable to handle kernel paging request at virtual address 00330a656369768a
[   10.441620] [00330a656369768a] address between user and kernel address ranges
[   10.449087] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[   10.454762] Modules linked in: brcmfmac vc4 drm_kms_helper cfg80211 drm rfkill smsc95xx brcmutil usbnet drm_panel_orientation_quirks raspberrypi_hwmon bcm2835_dma crc32_ce pwm_bcm2835 bcm2835_rng virt_dma rng_core i2c_bcm2835 ip_tables x_tables ipv6
[   10.477296] CPU: 2 PID: 45 Comm: kworker/2:1 Not tainted 4.19.0-rc5 #3
[   10.483934] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT)
[   10.489966] Workqueue: events output_poll_execute [drm_kms_helper]
[   10.596515] Process kworker/2:1 (pid: 45, stack limit = 0x000000007e8924dc)
[   10.603590] Call trace:
[   10.606259]  drm_client_dev_hotplug+0x5c/0xb0 [drm]
[   10.611303]  drm_kms_helper_hotplug_event+0x30/0x40 [drm_kms_helper]
[   10.617849]  output_poll_execute+0xc4/0x1e0 [drm_kms_helper]
[   10.623616]  process_one_work+0x1c8/0x318
[   10.627695]  worker_thread+0x48/0x428
[   10.631420]  kthread+0xf8/0x128
[   10.634615]  ret_from_fork+0x10/0x18
[   10.638255] Code: 54000220 f9401261 aa1303e0 b4000141 (f9400c21)
[   10.644456] ---[ end trace c75b4a4b0e141908 ]---

The reason for this is that drm_fbdev_cma_init() removes the drm_client
when fbdev registration fails, but it doesn't remove the client from the
drm_device client list. So the client list now has a pointer that points
into the unknown and we have a 'use after free' situation.

Split drm_client_new() into drm_client_init() and drm_client_add() to fix
removal in the error path.

Fixes: 894a677f ("drm/cma-helper: Use the generic fbdev emulation")
Reported-by: default avatarSergey Suloev <ssuloev@orpaltech.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001194536.57756-1-noralf@tronnes.org
      4d4c2d89
    • Jann Horn's avatar
      drm: fix use-after-free read in drm_mode_create_lease_ioctl() · 12d43deb
      Jann Horn authored 
      

fd_install() moves the reference given to it into the file descriptor table
of the current process. If the current process is multithreaded, then
immediately after fd_install(), another thread can close() the file
descriptor and cause the file's resources to be cleaned up.

Since the reference to "lessee" is held by the file, we must not access
"lessee" after the fd_install() call.

As far as I can tell, to reach this codepath, the caller must have an open
file descriptor to a DRI device in master mode. I'm not sure what the
requirements for that are.

Signed-off-by: default avatarJann Horn <jannh@google.com>
Fixes: 62884cd3 ("drm: Add four ioctls for managing drm mode object leases [v7]")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001153117.216923-1-jannh@google.com
      12d43deb
  13. Sep 30, 2018
  15. Sep 29, 2018
  17. Sep 28, 2018
  19. Sep 27, 2018
    • Guoju Fang's avatar
      bcache: add separate workqueue for journal_write to avoid deadlock · 0f843e65
      Guoju Fang authored 
      

After write SSD completed, bcache schedules journal_write work to
system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM
flag. system_wq is also a bound wq, and there may be no idle kworker on
current processor. Creating a new kworker may unfortunately need to
reclaim memory first, by shrinking cache and slab used by vfs, which
depends on bcache device. That's a deadlock.

This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM
flag. It's rescuer thread will work to avoid the deadlock.

Signed-off-by: default avatarGuoju Fang <fangguoju@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarColy Li <colyli@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      0f843e65