On 8/17/2018 5:06 AM, Stephen Boyd wrote:

We got a bug report that this function oopses when trying to do a kasprintf().

PC is at string+0x2c/0x60 LR is at vsnprintf+0x28c/0x4ec pc : [<ffffff80088d35d8>] lr : [<ffffff80088d5fc4>] pstate: a0c00049 sp : ffffff80095fb540 x29: ffffff80095fb540 x28: ffffff8008ad42bc x27: 00000000ffffffd8 x26: 0000000000000000 x25: ffffff8008c216c8 x24: 0000000000000000 x23: 0000000000000000 x22: ffffff80095fb720 x21: 0000000000000000 x20: ffffff80095fb720 x19: ffffff80095fb6f0 x18: 000000000000000a x17: 00000000b42ba473 x16: ffffff800805bbe8 x15: 00000000000a157d x14: 000000000000000c x13: 0000000000000000 x12: 0000ffff0000000f x11: 0000000000000003 x10: 0000000000000001 x9 : 0000000000000040 x8 : 000000000000001c x7 : ffffffffffffffff x6 : 0000000000000000 x5 : 0000000000000228 x4 : 0000000000000000 x3 : ffff0a00ffffff04 x2 : 0000000000007961 x1 : 0000000000000000 x0 : 0000000000000000 Process kworker/3:1 (pid: 61, stack limit = 0xffffff80095f8000) Call trace: Exception stack(0xffffff80095fb400 to 0xffffff80095fb540) b400: 0000000000000000 0000000000000000 0000000000007961 ffff0a00ffffff04 b420: 0000000000000000 0000000000000228 0000000000000000 ffffffffffffffff b440: 000000000000001c 0000000000000040 0000000000000001 0000000000000003 b460: 0000ffff0000000f 0000000000000000 000000000000000c 00000000000a157d b480: ffffff800805bbe8 00000000b42ba473 000000000000000a ffffff80095fb6f0 b4a0: ffffff80095fb720 0000000000000000 ffffff80095fb720 0000000000000000 b4c0: 0000000000000000 ffffff8008c216c8 0000000000000000 00000000ffffffd8 b4e0: ffffff8008ad42bc ffffff80095fb540 ffffff80088d5fc4 ffffff80095fb540 b500: ffffff80088d35d8 00000000a0c00049 ffffff80095fb550 ffffff80080d06a4 b520: ffffffffffffffff ffffff80088d5e0c ffffff80095fb540 ffffff80088d35d8 [<ffffff80088d35d8>] string+0x2c/0x60 [<ffffff80088d5fc4>] vsnprintf+0x28c/0x4ec [<ffffff80083973b8>] kvasprintf+0x68/0x100 [<ffffff800839755c>] kasprintf+0x60/0x80 [<ffffff800849cc24>] drm_encoder_init+0x134/0x164 [<ffffff80084d9a7c>] dpu_encoder_init+0x60/0x94 [<ffffff80084eced0>] _dpu_kms_drm_obj_init+0xa0/0x424 [<ffffff80084ed870>] dpu_kms_hw_init+0x61c/0x6bc [<ffffff80084f7614>] msm_drm_bind+0x380/0x67c [<ffffff80085114e4>] try_to_bring_up_master+0x228/0x264 [<ffffff80085116e8>] component_master_add_with_match+0x90/0xc0 [<ffffff80084f722c>] msm_pdev_probe+0x260/0x2c8 [<ffffff800851a910>] platform_drv_probe+0x58/0xa8 [<ffffff80085185c8>] driver_probe_device+0x2d8/0x40c [<ffffff8008518928>] __device_attach_driver+0xd4/0x10c [<ffffff800851644c>] bus_for_each_drv+0xb4/0xd0 [<ffffff8008518230>] __device_attach+0xd0/0x160 [<ffffff8008518984>] device_initial_probe+0x24/0x30 [<ffffff800851744c>] bus_probe_device+0x38/0x98 [<ffffff8008517aac>] deferred_probe_work_func+0x144/0x148 [<ffffff80080c8654>] process_one_work+0x218/0x3bc [<ffffff80080c883c>] process_scheduled_works+0x44/0x48 [<ffffff80080c95bc>] worker_thread+0x288/0x32c [<ffffff80080cea30>] kthread+0x134/0x13c [<ffffff8008084750>] ret_from_fork+0x10/0x18 Code: 910003fd 2a0403e6 eb0400ff 54000060 (38646845)

Looking at the code I see that drm_encoder_init() is called from the DPU code with 'DRM_MODE_CONNECTOR_DSI' passed in as the 'encoder_type' argument (follow from _dpu_kms_initialize_dsi()). That corresponds to the integer 16. That is then indexed into drm_encoder_enum_list in drm_encoder_init() to look up the name of the encoder. If you're still following along, that's an encoder not a connector! We really want to use DRM_MODE_ENCODER_DSI (integer 6) instead of DRM_MODE_CONNECTOR_DSI here, or we'll go out of bounds of the encoder array. Pass the right thing and everything is fine.

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

---

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c index 7dd6bd2d6d37..74cc204b07e8 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c @@ -450,7 +450,7 @@ static void _dpu_kms_initialize_dsi(struct drm_device *dev, int i, rc;

/*TODO: Support two independent DSI connectors */

• encoder = dpu_encoder_init(dev, DRM_MODE_CONNECTOR_DSI);

• encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_DSI); if (IS_ERR_OR_NULL(encoder)) { DPU_ERROR("encoder init failed for dsi display\n"); return;

I have tested this on sdm845 mtp and it does fix the issue. Tested-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org