[PATCH] gpu/drm/msm: fix shutdown hook in case GPU components failed to bind

[abhinavk at codeaurora.org]

On 2021-03-01 13:41, Dmitry Baryshkov wrote:
> if GPU components have failed to bind, shutdown callback would fail 
> with
> the following backtrace. Add safeguard check to stop that oops from
> happening and allow the board to reboot.
> 
> [   66.617046] Unable to handle kernel NULL pointer dereference at
> virtual address 0000000000000000
> [   66.626066] Mem abort info:
> [   66.628939]   ESR = 0x96000006
> [   66.632088]   EC = 0x25: DABT (current EL), IL = 32 bits
> [   66.637542]   SET = 0, FnV = 0
> [   66.640688]   EA = 0, S1PTW = 0
> [   66.643924] Data abort info:
> [   66.646889]   ISV = 0, ISS = 0x00000006
> [   66.650832]   CM = 0, WnR = 0
> [   66.653890] user pgtable: 4k pages, 48-bit VAs, 
> pgdp=0000000107f81000
> [   66.660505] [0000000000000000] pgd=0000000100bb2003,
> p4d=0000000100bb2003, pud=0000000100897003, pmd=0000000000000000
> [   66.671398] Internal error: Oops: 96000006 [#1] PREEMPT SMP
> [   66.677115] Modules linked in:
> [   66.680261] CPU: 6 PID: 352 Comm: reboot Not tainted
> 5.11.0-rc2-00309-g79e3faa756b2 #38
> [   66.688473] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 
> (DT)
> [   66.695347] pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
> [   66.701507] pc : msm_atomic_commit_tail+0x78/0x4e0
> [   66.706437] lr : commit_tail+0xa4/0x184
> [   66.710381] sp : ffff8000108f3af0
> [   66.713791] x29: ffff8000108f3af0 x28: ffff418c44337000
> [   66.719242] x27: 0000000000000000 x26: ffff418c40a24490
> [   66.724693] x25: ffffd3a842a4f1a0 x24: 0000000000000008
> [   66.730146] x23: ffffd3a84313f030 x22: ffff418c444ce000
> [   66.735598] x21: ffff418c408a4980 x20: 0000000000000000
> [   66.741049] x19: 0000000000000000 x18: ffff800010710fbc
> [   66.746500] x17: 000000000000000c x16: 0000000000000001
> [   66.751954] x15: 0000000000010008 x14: 0000000000000068
> [   66.757405] x13: 0000000000000001 x12: 0000000000000000
> [   66.762855] x11: 0000000000000001 x10: 00000000000009b0
> [   66.768306] x9 : ffffd3a843192000 x8 : ffff418c44337000
> [   66.773757] x7 : 0000000000000000 x6 : 00000000a401b34e
> [   66.779210] x5 : 00ffffffffffffff x4 : 0000000000000000
> [   66.784660] x3 : 0000000000000000 x2 : ffff418c444ce000
> [   66.790111] x1 : ffffd3a841dce530 x0 : ffff418c444cf000
> [   66.795563] Call trace:
> [   66.798075]  msm_atomic_commit_tail+0x78/0x4e0
> [   66.802633]  commit_tail+0xa4/0x184
> [   66.806217]  drm_atomic_helper_commit+0x160/0x390
> [   66.811051]  drm_atomic_commit+0x4c/0x60
> [   66.815082]  drm_atomic_helper_disable_all+0x1f4/0x210
> [   66.820355]  drm_atomic_helper_shutdown+0x80/0x130
> [   66.825276]  msm_pdev_shutdown+0x14/0x20
> [   66.829303]  platform_shutdown+0x28/0x40
> [   66.833330]  device_shutdown+0x158/0x330
> [   66.837357]  kernel_restart+0x40/0xa0
> [   66.841122]  __do_sys_reboot+0x228/0x250
> [   66.845148]  __arm64_sys_reboot+0x28/0x34
> [   66.849264]  el0_svc_common.constprop.0+0x74/0x190
> [   66.854187]  do_el0_svc+0x24/0x90
> [   66.857595]  el0_svc+0x14/0x20
> [   66.860739]  el0_sync_handler+0x1a4/0x1b0
> [   66.864858]  el0_sync+0x174/0x180
> [   66.868269] Code: 1ac020a0 2a000273 eb02007f 54ffff01 (f9400285)
> [   66.874525] ---[ end trace 20dedb2a3229fec8 ]---
> 
> Fixes: 9d5cbf5fe46e ("drm/msm: add shutdown support for display
> platform_driver")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk at codeaurora.org>
> ---
>  drivers/gpu/drm/msm/msm_atomic.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_atomic.c 
> b/drivers/gpu/drm/msm/msm_atomic.c
> index 6a326761dc4a..2fd0cf6421ad 100644
> --- a/drivers/gpu/drm/msm/msm_atomic.c
> +++ b/drivers/gpu/drm/msm/msm_atomic.c
> @@ -207,7 +207,12 @@ void msm_atomic_commit_tail(struct 
> drm_atomic_state *state)
>  	struct msm_kms *kms = priv->kms;
>  	struct drm_crtc *async_crtc = NULL;
>  	unsigned crtc_mask = get_crtc_mask(state);
> -	bool async = kms->funcs->vsync_time &&
> +	bool async;
> +
> +	if (!kms)
> +		return;
> +
> +	async = kms->funcs->vsync_time &&
>  			can_do_async(state, &async_crtc);
> 
>  	trace_msm_atomic_commit_tail_start(async, crtc_mask);