From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 247B1C982FA for ; Tue, 22 Sep 2026 20:56:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 586A910EE6C; Tue, 22 Sep 2026 20:56:40 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="IkeTx1yy"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id CF90010EE6C for ; Tue, 22 Sep 2026 20:56:38 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id B8CDF4029D; Tue, 22 Sep 2026 20:56:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B1DE1F000FF; Tue, 22 Sep 2026 20:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790110598; bh=N5Aew1QGpcGcgAL56cWdmFKQOzCE8HnWBXPBVpQMGY0=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=IkeTx1yy3ISSpJjMrAsgbJZKGW5yO38MIePUCBsLPsnjaC0OsXXeZVgqUBFa0mbyg jJtzD865/zvxEk7wcZy+HbzSSbgp1uLlw6POWG9oYpsyDVEAec3dKNuxIPPXN/tUCM 0/kPsRb+/JsuNfJrgNpIDarciirVU1Cpt929bX2tsjLi095by8MIFU6N3jIi6PB41s q3BeEQttvDUqVFamN2Mbb+/rEw+PK4d0nMYIkOWdtSQJQ7KVDndpOYKw57L2N0kVKa X97DhHF2K6rBWcDVWyRpneMoFAsNq3bgtcxSKN0fllMUVTHKVmoEJMpZOS08bgfwn1 IRvrqLPXDagTQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH v1 15/27] drm/panthor: Add AM_RESOURCE_GROUP support To: "Karunika Choo" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20260922204535.2850094-16-karunika.choo@arm.com> References: <20260922204535.2850094-1-karunika.choo@arm.com> <20260922204535.2850094-16-karunika.choo@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 22 Sep 2026 20:56:38 +0000 Message-Id: <20260922205638.7B1DE1F000FF@smtp.kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 5 potential issue(= s) to consider: - [High] Runtime PM handling missing in shared IRQ handler - [High] Missing synchronize_irq() during runtime suspend - [High] CPU busy-loop in message retry workqueue - [Medium] Missing NULL pointer checks for devm_kasprintf allocations - [Low] Uninitialized irq field in panthor_resource_group -- commit 97f87eba41075ad8e7f232b378d4561b841f68e5 Author: Karunika Choo drm/panthor: Add AM_RESOURCE_GROUP support Add resource-group probing for the arbitration device, including MMIO resources, IRQ handling, per-AW AM message helpers, handshake negotiation, and retry work for deferred outgoing messages. Hook resource groups into arbitration init, teardown, and runtime PM. > diff --git a/drivers/gpu/drm/panthor/arbitration/panthor_resource_group.c= b/drivers/gpu/drm/panthor/arbitration/panthor_resource_group.c > new file mode 100644 > --- /dev/null > +++ b/drivers/gpu/drm/panthor/arbitration/panthor_resource_group.c > @@ -0,0 +1,323 @@ [ ... ] > +static void rg_retry_messages(struct work_struct *work) > +{ [ ... ] > + if (retry) > + queue_work(rg->wq, &rg->msg_retry_work); [Severity: High] Could this sequence lead to a CPU busy-loop? If the hardware has pending messages and panthor_am_msg_retry() returns -EBUSY or -EAGAIN, this will immediately requeue the work. Because it is an ordered workqueue and no delay is specified, does this cause the worker thread to monopolize the CPU at 100% until the hardware processes the messages? [ ... ] > +static irqreturn_t rg_irq_raw_handler(int irq, void *data) > +{ > + struct panthor_resource_group *rg =3D data; > + unsigned long message_mask; > + u32 status; > + u8 aw_id; > + > + status =3D gpu_read(rg->iomem, AM_RG_IRQ_STATUS); > + if (!status) > + return IRQ_NONE; [Severity: High] Is it safe to perform this MMIO read without verifying device activity? Since the IRQ is registered with IRQF_SHARED, this handler can be invoked by other devices on the same line while this device is in runtime suspend. If the device is powered down, the read will typically return ~0u, which bypasses the !status check and could result in spurious processing of 16 pending messages. Should this use pm_runtime_get_if_active() to verify the device is awake before accessing hardware? [ ... ] > +int panthor_resource_group_suspend(struct panthor_arbitration *adev) > +{ > + for (int i =3D 0; i < AM_ARB_MAX_RG_COUNT; i++) { > + struct panthor_resource_group *rg =3D adev->rg[i]; > + > + if (!rg) > + continue; > + > + rg_irq_suspend(rg); > + } > + > + return 0; > +} [Severity: High] Does this suspend sequence need to wait for in-flight interrupts? The IRQ is masked at the device level, but since it is registered as IRQF_SHARED, rg_irq_raw_handler() might still be executing concurrently on another CPU. Should there be a synchronize_irq() call here to prevent the device from powering down while the handler is still running? [ ... ] > +static int resource_group_init(struct panthor_arbitration *adev, > + const struct fwnode_handle *child) > +{ [ ... ] > + rg =3D devm_kzalloc(dev, sizeof(*rg), GFP_KERNEL); > + if (!rg) > + return -ENOMEM; > + > + name =3D devm_kasprintf(dev, GFP_KERNEL, "rg%d", res.id); [Severity: Medium] Could name be NULL here under memory pressure? devm_kasprintf() isn't checked for allocation failure before being passed into functions expecting valid strings, like devm_alloc_ordered_workqueue() below. [ ... ] > + irq =3D fwnode_irq_get(child, 0); > + if (irq < 0) > + return dev_err_probe(dev, irq, "%s: Failed to get IRQ", name); > + > + irqdata =3D irq_get_irq_data(irq); > + if (irqdata) > + irq_flags =3D irqd_get_trigger_type(irqdata); [Severity: Low] Should the retrieved IRQ number be stored in rg->irq here? The local irq variable is populated and used for requesting the interrupt, but it doesn't appear to be assigned to the structure field for future use. > + > + ret =3D devm_request_irq( > + dev, irq, rg_irq_raw_handler, irq_flags | IRQF_SHARED, > + devm_kasprintf(dev, GFP_KERNEL, "panthor-%s-irq", name), rg); [Severity: Medium] Similar to the earlier devm_kasprintf() call, could this inner allocation fail and pass a NULL device name to devm_request_irq()? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260922204535.2850= 094-1-karunika.choo@arm.com?part=3D15