From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5AB55606A319 for ; Tue, 20 Oct 2026 08:09:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=e7YaLmxD Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C06D410F36C; Tue, 20 Oct 2026 08:09:41 +0000 (UTC) Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 577D110F36C for ; Tue, 20 Oct 2026 08:09:35 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 2874941A85; Tue, 20 Oct 2026 08:09:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA87A1F000C4; Tue, 20 Oct 2026 08:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792483775; bh=PWlx/Vuh6oFuKA/S0KvTXxS61rcQXfBwyRa+Pc16cjA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=e7YaLmxDiSbCXH2Eh7myOfk6eGQL5M2GIWE1Nw62YTgg9mtTc3MU4ujOjIdO/y9jo WNuaYnbVi4xtrAumUu685Imuk2N6eU+1Zocf2Fj9PJqkFNLiKmiygkbLanxLJvXTW3 pS9zgjcfTFbsXgtEycDhmkKVhnsz7GbO89i5Wn0PULyADOpJkMnvaGVvQcdsLBt1yl H9JLH/REHclS3T+yZklz+LHZPC2AZJI0UgcSf9w0MrooJgQzCCSdbM2zORB+F2XtlR eYvqrGQ3ZOYHu2wMaSQ90ZS+z9jsSK0Yl3Ucjlc9I1LptpenaRRubAJ1mPlAdOCcxr bHajBh0joi/mA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 2/3] drm/msm/a5xx: Hold a CPU latency request while the GPU is powered To: "Fabricio Akio" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20261019-a5xx-gpu-pm-v2-2-457aafbb28da@gmail.com> References: <20261019-a5xx-gpu-pm-v2-0-457aafbb28da@gmail.com> <20261019-a5xx-gpu-pm-v2-2-457aafbb28da@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Oct 2026 08:09:34 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "dri-devel" X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] drm/msm/a5xx: premature pm_qos_req removal in a5xx_destroy() befor= e cleanup -- commit fc8618fd147137559c55740f177ada72c5eca286 Author: Fabricio Akio drm/msm/a5xx: Hold a CPU latency request while the GPU is powered This patch holds a CPU latency QoS request while A508, A509, and A512 GPUs are powered on so the SoC does not enter system-level power collapse while GPU work is active. The request is added on GPU resume and removed on GPU suspend or destruction. > diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/= adreno/a5xx_gpu.c > index 0aff8252a00f9..1d4993f8cb7c4 100644 > --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c > +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c > @@ -1060,6 +1060,10 @@ static void a5xx_destroy(struct msm_gpu *gpu) > drm_gem_object_put(a5xx_gpu->shadow_bo); > } > =20 > + /* Still held if suspending the GPU failed before it was destroyed */ > + if (cpu_latency_qos_request_active(&a5xx_gpu->pm_qos_req)) > + cpu_latency_qos_remove_request(&a5xx_gpu->pm_qos_req); > + > adreno_gpu_cleanup(adreno_gpu); > kfree(a5xx_gpu); > } [Severity: High] Should the removal of a5xx_gpu->pm_qos_req in a5xx_destroy() happen after adreno_gpu_cleanup(adreno_gpu) rather than before it? In adreno_unbind(), if adreno_system_suspend() fails (for example, timing out with -EBUSY because a GPU submission is hung or still active, or if pm_runtime_force_suspend() fails), adreno_system_suspend() restarts the scheduler and returns with runtime PM still enabled: drivers/gpu/drm/msm/adreno/adreno_device.c:adreno_system_suspend() { remaining =3D wait_event_timeout(gpu->retire_event, gpu->active_submits =3D=3D 0, msecs_to_jiffies(1000)); if (remaining =3D=3D 0) { dev_err(dev, "Timeout waiting for GPU to suspend\n"); ret =3D -EBUSY; goto out; } ret =3D pm_runtime_force_suspend(dev); out: if (ret) resume_scheduler(gpu); } adreno_unbind() then proceeds directly into gpu->funcs->destroy(gpu) -> a5xx_destroy() while runtime PM and gpu->worker are still running. Runtime PM is only disabled and gpu->worker is only stopped inside adreno_gpu_cleanup() -> msm_gpu_cleanup(): drivers/gpu/drm/msm/adreno/adreno_gpu.c:adreno_gpu_cleanup() { ... pm_runtime_dont_use_autosuspend(&gpu->pdev->dev); if (priv && pm_runtime_enabled(&priv->gpu_pdev->dev)) pm_runtime_disable(&priv->gpu_pdev->dev); msm_gpu_cleanup(&adreno_gpu->base); } Meanwhile, recover_worker on gpu->worker runs a5xx_recover() -> adreno_recover(), which directly calls gpu->funcs->pm_suspend(gpu) and gpu->funcs->pm_resume(gpu). If cpu_latency_qos_remove_request(&a5xx_gpu->pm_qos_req) runs before adreno_gpu_cleanup(adreno_gpu), can recover_worker or runtime PM execute a5xx_pm_suspend() or a5xx_pm_resume() concurrently with or after the removal, re-adding &a5xx_gpu->pm_qos_req to cpu_latency_constraints right before kfree(a5xx_gpu) frees it? [ ... ] > > base-commit: 2efb7a11f1aa4d2dc285fe2680cca22cb9f72f64 Boris =E5=9C=A8=E8=BF=9B=E8=A1=8C=E6=B7=B1=E5=85=A5=E5=AE=A1=E6=9F=A5=E6=97=B6=EF= =BC=8C=E6=88=91=E5=8F=91=E7=8E=B0=E4=BA=86=E4=B8=80=E4=B8=AA=E6=BD=9C=E5=9C= =A8=E7=9A=84=E9=87=8A=E6=94=BE=E5=90=8E=E4=BD=BF=E7=94=A8=EF=BC=88Use-After= -Free=EF=BC=89=E9=97=AE=E9=A2=98=EF=BC=8C=E5=B7=B2=E5=9C=A8=E4=B8=8A=E9=9D= =A2=E7=9A=84=E5=86=85=E8=81=94=E8=AF=84=E8=AE=BA=E4=B8=AD=E8=AF=A6=E7=BB=86= =E8=AF=B4=E6=98=8E=E3=80=82 --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261019-a5xx-gpu-p= m-v2-0-457aafbb28da@gmail.com?part=3D2