diff options
| author | Stephen Boyd <swboyd@chromium.org> | 2020-09-01 14:59:41 -0700 |
|---|---|---|
| committer | Rob Clark <robdclark@chromium.org> | 2020-09-09 15:24:44 -0700 |
| commit | 22f760941844dbcee6ee446e1896532f6dff01ef (patch) | |
| tree | 242cae86ea4fc076d5865350bd27e2f78394be86 /drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | |
| parent | e12e5263bf1d8dae2f1fd0a3163f88349404c277 (diff) | |
| download | linux-22f760941844dbcee6ee446e1896532f6dff01ef.tar.bz2 | |
drm/msm: Avoid div-by-zero in dpu_crtc_atomic_check()
The cstate->num_mixers member is only set to a non-zero value once
dpu_encoder_virt_mode_set() is called, but the atomic check function can
be called by userspace before that. Let's avoid the div-by-zero here and
inside _dpu_crtc_setup_lm_bounds() by skipping this part of the atomic
check if dpu_encoder_virt_mode_set() hasn't been called yet. This fixes
an UBSAN warning:
UBSAN: Undefined behaviour in drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c:860:31
division by zero
CPU: 7 PID: 409 Comm: frecon Tainted: G S 5.4.31 #128
Hardware name: Google Trogdor (rev0) (DT)
Call trace:
dump_backtrace+0x0/0x14c
show_stack+0x20/0x2c
dump_stack+0xa0/0xd8
__ubsan_handle_divrem_overflow+0xec/0x110
dpu_crtc_atomic_check+0x97c/0x9d4
drm_atomic_helper_check_planes+0x160/0x1c8
drm_atomic_helper_check+0x54/0xbc
drm_atomic_check_only+0x6a8/0x880
drm_atomic_commit+0x20/0x5c
drm_atomic_helper_set_config+0x98/0xa0
drm_mode_setcrtc+0x308/0x5dc
drm_ioctl_kernel+0x9c/0x114
drm_ioctl+0x2ac/0x4b0
drm_compat_ioctl+0xe8/0x13c
__arm64_compat_sys_ioctl+0x184/0x324
el0_svc_common+0xa4/0x154
el0_svc_compat_handler+0x
Cc: Abhinav Kumar <abhinavk@codeaurora.org>
Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: Sean Paul <seanpaul@chromium.org>
Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Diffstat (limited to 'drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c')
| -rw-r--r-- | drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c index 999e3bfc7452..3114a67dd7ac 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c @@ -824,7 +824,7 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc, struct drm_plane *plane; struct drm_display_mode *mode; - int cnt = 0, rc = 0, mixer_width, i, z_pos; + int cnt = 0, rc = 0, mixer_width = 0, i, z_pos; struct dpu_multirect_plane_states multirect_plane[DPU_STAGE_MAX * 2]; int multirect_count = 0; @@ -849,9 +849,11 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc, memset(pipe_staged, 0, sizeof(pipe_staged)); - mixer_width = mode->hdisplay / cstate->num_mixers; + if (cstate->num_mixers) { + mixer_width = mode->hdisplay / cstate->num_mixers; - _dpu_crtc_setup_lm_bounds(crtc, state); + _dpu_crtc_setup_lm_bounds(crtc, state); + } crtc_rect.x2 = mode->hdisplay; crtc_rect.y2 = mode->vdisplay; |