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 <[email protected]> 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 = data; > + unsigned long message_mask; > + u32 status; > + u8 aw_id; > + > + status = 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 = 0; i < AM_ARB_MAX_RG_COUNT; i++) { > + struct panthor_resource_group *rg = 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 = devm_kzalloc(dev, sizeof(*rg), GFP_KERNEL); > + if (!rg) > + return -ENOMEM; > + > + name = 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 = fwnode_irq_get(child, 0); > + if (irq < 0) > + return dev_err_probe(dev, irq, "%s: Failed to get IRQ", name); > + > + irqdata = irq_get_irq_data(irq); > + if (irqdata) > + irq_flags = 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 = 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()? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=15
