Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues: - [High] Calling drm_sched_job_cleanup() on an uninitialized struct drm_sched_job causes a NULL pointer dereference in the ethosu_ioctl_submit_job() error path. - [High] The shared IRQ handler accesses hardware registers without ensuring the device is active via Runtime PM, and the suspend callback fails to synchronize IRQs, risking fatal bus faults. -- --- Patch [5]: [PATCH v2 5/5] accel/ethosu: fix job completion fence cleanup --- commit b390c1806154d7460d3ff212d56c250283785f11 Author: GuoHan Zhao <[email protected]> Subject: accel/ethosu: fix job completion fence cleanup This commit addresses memory leaks and refcount underflows in the Ethos-U NPU driver's job cleanup path. It ensures that the done_fence is properly released during error cleanup and uses dma_fence_was_initialized() to handle raw allocations gracefully. Link: https://sashiko.dev/#/patchset/[email protected]?part=1 > diff --git a/drivers/accel/ethosu/ethosu_job.c > b/drivers/accel/ethosu/ethosu_job.c > index 5847433e87e7e..b68a905d22f83 100644 > --- a/drivers/accel/ethosu/ethosu_job.c > +++ b/drivers/accel/ethosu/ethosu_job.c > @@ -152,6 +152,13 @@ static void ethosu_job_err_cleanup(struct ethosu_job > *job) > > drm_gem_object_put(job->cmd_bo); > > + if (job->done_fence) { > + if (dma_fence_was_initialized(job->done_fence)) > + dma_fence_put(job->done_fence); > + else > + dma_fence_free(job->done_fence); > + } > + > kfree(job); > } > [Severity: High] This is a pre-existing issue, but was not introduced by this patch. When the done_fence allocation fails in ethosu_ioctl_submit_job(), it jumps to out_cleanup_job: drivers/accel/ethosu/ethosu_job.c:ethosu_ioctl_submit_job() { ... if (!ejob->done_fence) { ret = -ENOMEM; goto out_cleanup_job; } ... out_cleanup_job: if (ret) drm_sched_job_cleanup(&ejob->base); } Because drm_sched_job_init() was not called yet, ejob->base is completely zero-initialized, meaning ejob->base.s_fence is NULL. When drm_sched_job_cleanup() attempts to read the refcount: drivers/gpu/drm/scheduler/sched_main.c:drm_sched_job_cleanup() { ... if (kref_read(&job->s_fence->finished.refcount)) { ... } Will this result in a NULL pointer dereference because the function assumes job->s_fence is a valid pointer? [Severity: High] This isn't a bug introduced by this patch, but there appears to be an issue with how shared interrupts interact with runtime PM. The NPU interrupt is registered with the IRQF_SHARED flag: drivers/accel/ethosu/ethosu_job.c:ethosu_job_init() { ... ret = devm_request_threaded_irq(dev, edev->irq, ethosu_job_irq_handler, ethosu_job_irq_handler_thread, IRQF_SHARED, KBUILD_MODNAME, edev); ... } If another device sharing the IRQ line triggers an interrupt while the NPU is runtime-suspended, the handler executes and reads MMIO registers: drivers/accel/ethosu/ethosu_job.c:ethosu_job_irq_handler() { ... u32 status = readl_relaxed(dev->regs + NPU_REG_STATUS); if (!(status & STATUS_IRQ_RAISED)) return IRQ_NONE; ... } Could this unconditionally read registers without verifying the device's PM state via pm_runtime_get_if_active()? Furthermore, the runtime suspend callback disables clocks: drivers/accel/ethosu/ethosu_drv.c:ethosu_device_suspend() { ... clk_bulk_disable_unprepare(ethosudev->num_clks, ethosudev->clks); return 0; } Since this doesn't call synchronize_irq() to wait for executing handlers, could concurrent IRQ execution cause invalid hardware writes or a bus fault when accessing powered-off MMIO registers? > @@ -162,7 +169,6 @@ static void ethosu_job_cleanup(struct kref *ref) > > pm_runtime_put_autosuspend(job->dev->base.dev); > > - dma_fence_put(job->done_fence); > dma_fence_put(job->inference_done_fence); > > ethosu_job_err_cleanup(job); -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=5
