From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Rob Clark <robdclark@gmail.com>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
Sean Paul <sean@poorly.run>,
Abhinav Kumar <abhinavk@codeaurora.org>,
Jeykumar Sankaran <jsanka@codeaurora.org>,
Jordan Crouse <jcrouse@codeaurora.org>,
Sean Paul <seanpaul@chromium.org>,
linux-arm-msm-owner@vger.kernel.org
Subject: Re: [PATCH 1/2] drm/msm: Avoid div-by-zero in dpu_crtc_atomic_check()
Date: Wed, 02 Sep 2020 12:35:30 +0530 [thread overview]
Message-ID: <b8ee3f88265f9aa510eef566f68532a0@codeaurora.org> (raw)
In-Reply-To: <20200901215942.2559119-2-swboyd@chromium.org>
On 2020-09-02 03:29, Stephen Boyd wrote:
> 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>
> ---
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
WARNING: multiple messages have this Message-ID (diff)
From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Stephen Boyd <swboyd@chromium.org>
Cc: freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
Sean Paul <seanpaul@chromium.org>,
Abhinav Kumar <abhinavk@codeaurora.org>,
Sean Paul <sean@poorly.run>,
linux-arm-msm-owner@vger.kernel.org
Subject: Re: [PATCH 1/2] drm/msm: Avoid div-by-zero in dpu_crtc_atomic_check()
Date: Wed, 02 Sep 2020 12:35:30 +0530 [thread overview]
Message-ID: <b8ee3f88265f9aa510eef566f68532a0@codeaurora.org> (raw)
In-Reply-To: <20200901215942.2559119-2-swboyd@chromium.org>
On 2020-09-02 03:29, Stephen Boyd wrote:
> 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>
> ---
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
_______________________________________________
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dri-devel@lists.freedesktop.org
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next prev parent reply other threads:[~2020-09-02 7:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-01 21:59 [PATCH 0/2] A couple drm/msm fixes Stephen Boyd
2020-09-01 21:59 ` Stephen Boyd
2020-09-01 21:59 ` [PATCH 1/2] drm/msm: Avoid div-by-zero in dpu_crtc_atomic_check() Stephen Boyd
2020-09-01 21:59 ` Stephen Boyd
2020-09-01 22:05 ` abhinavk
2020-09-01 22:05 ` abhinavk
2020-09-02 7:05 ` Sai Prakash Ranjan [this message]
2020-09-02 7:05 ` Sai Prakash Ranjan
2020-09-01 21:59 ` [PATCH 2/2] drm/msm: Drop debug print in _dpu_crtc_setup_lm_bounds() Stephen Boyd
2020-09-01 21:59 ` Stephen Boyd
2020-09-01 22:06 ` abhinavk
2020-09-01 22:06 ` abhinavk
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