drm/msm: Fix devfreq NULL pointer dereference on a3xx

Browse source

There is no devfreq on a3xx at the moment since gpu_busy is not
implemented. This means that msm_devfreq_init() will return early
and the entire devfreq setup is skipped.

However, msm_devfreq_active() and msm_devfreq_idle() are still called
unconditionally later, causing a NULL pointer dereference:

  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
  Internal error: Oops: 96000004 [#1] PREEMPT SMP
  CPU: 0 PID: 133 Comm: ring0 Not tainted 5.15.0-rc1 #4
  Hardware name: Longcheer L8150 (DT)
  pc : mutex_lock_io+0x2bc/0x2f0
  lr : msm_devfreq_active+0x3c/0xe0 [msm]
  Call trace:
   mutex_lock_io+0x2bc/0x2f0
   msm_gpu_submit+0x164/0x180 [msm]
   msm_job_run+0x54/0xe0 [msm]
   drm_sched_main+0x2b0/0x4a0 [gpu_sched]
   kthread+0x154/0x160
   ret_from_fork+0x10/0x20

Fix this by adding a check in msm_devfreq_active/idle() which ensures
that devfreq was actually initialized earlier.

Fixes: 9bc9557017 ("drm/msm: Devfreq tuning")
Reported-by: Nikita Travkin <nikita@trvn.ru>
Tested-by: Nikita Travkin <nikita@trvn.ru>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210913164556.16284-1-stephan@gerhold.net
Signed-off-by: Rob Clark <robdclark@chromium.org>

...

This commit is contained in:

Stephan Gerhold 2021-09-13 18:45:56 +02:00 • committed by Rob Clark

parent 9463b64d1a

commit efb8a170a3

1 changed files with 6 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

drivers/gpu/drm/msm/msm_gpu_devfreq.c

View file