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Fri, 03 Jun 2022 02:46:05 -0700 (PDT) Received: from [192.168.1.211] ([37.153.55.125]) by smtp.gmail.com with ESMTPSA id f9-20020a2e6a09000000b00254319f8e63sm1223352ljc.91.2022.06.03.02.46.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 03 Jun 2022 02:46:05 -0700 (PDT) Message-ID: Date: Fri, 3 Jun 2022 12:46:04 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [v2] drm/msm: add null checks for drm device to avoid crash during probe defer Content-Language: en-GB To: Vinod Polimera , dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, robdclark@gmail.com, dianders@chromium.org, swboyd@chromium.org References: <1654249343-24959-1-git-send-email-quic_vpolimer@quicinc.com> From: Dmitry Baryshkov In-Reply-To: <1654249343-24959-1-git-send-email-quic_vpolimer@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/06/2022 12:42, Vinod Polimera wrote: > During probe defer, drm device is not initialized and an external > trigger to shutdown is trying to clean up drm device leading to crash. > Add checks to avoid drm device cleanup in such cases. > > BUG: unable to handle kernel NULL pointer dereference at virtual > address 00000000000000b8 > > Call trace: > > drm_atomic_helper_shutdown+0x44/0x144 > msm_pdev_shutdown+0x2c/0x38 > platform_shutdown+0x2c/0x38 > device_shutdown+0x158/0x210 > kernel_restart_prepare+0x40/0x4c > kernel_restart+0x20/0x6c > __arm64_sys_reboot+0x194/0x23c > invoke_syscall+0x50/0x13c > el0_svc_common+0xa0/0x17c > do_el0_svc_compat+0x28/0x34 > el0_svc_compat+0x20/0x70 > el0t_32_sync_handler+0xa8/0xcc > el0t_32_sync+0x1a8/0x1ac > > Changes in v2: > - Add fixes tag. > > Fixes: 623f279c778 ("drm/msm: fix shutdown hook in case GPU components failed to bind") > Signed-off-by: Vinod Polimera Also please remove bouncing quicinc.com emails from cc list > --- > drivers/gpu/drm/msm/msm_drv.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c > index 4448536..d62ac66 100644 > --- a/drivers/gpu/drm/msm/msm_drv.c > +++ b/drivers/gpu/drm/msm/msm_drv.c > @@ -142,6 +142,9 @@ static void msm_irq_uninstall(struct drm_device *dev) > struct msm_drm_private *priv = dev->dev_private; > struct msm_kms *kms = priv->kms; > > + if (!irq_has_action(kms->irq)) > + return; > + > kms->funcs->irq_uninstall(kms); > if (kms->irq_requested) > free_irq(kms->irq, dev); > @@ -259,6 +262,7 @@ static int msm_drm_uninit(struct device *dev) > > ddev->dev_private = NULL; > drm_dev_put(ddev); > + priv->dev = NULL; > > destroy_workqueue(priv->wq); > > @@ -1167,7 +1171,7 @@ void msm_drv_shutdown(struct platform_device *pdev) > struct msm_drm_private *priv = platform_get_drvdata(pdev); > struct drm_device *drm = priv ? priv->dev : NULL; > > - if (!priv || !priv->kms) > + if (!priv || !priv->kms || !drm) > return; > > drm_atomic_helper_shutdown(drm); -- With best wishes Dmitry