Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
Pre-existing issues: - [High] Asynchronous Runtime PM put on probe error path causes device to remain powered on. - [High] IRQ remains active while the DRM scheduler is destroyed on probe error and unbind, risking Use-After-Free. - [High] IRQ handler accesses hardware registers without PM runtime protection, causing bus faults. - [High] Memory leak of `done_fence` via user-controlled ioctl error path. -- commit 929da42114076da83041012a4812042cd457402a Author: Rob Herring (Arm) <[email protected]> accel: ethosu: Fix probe error cleanup This commit unwinds initialized resources on probe error paths to prevent leaks and leaves the hardware cleanly. It also prevents calling drm_sched_fini() on a failed scheduler initialization. > diff --git a/drivers/accel/ethosu/ethosu_drv.c > b/drivers/accel/ethosu/ethosu_drv.c > index f1af7b3ea0385..41ecfc623d425 100644 > --- a/drivers/accel/ethosu/ethosu_drv.c > +++ b/drivers/accel/ethosu/ethosu_drv.c > @@ -371,13 +371,23 @@ static int ethosu_probe(struct platform_device *pdev) > > ret = ethosu_init(ethosudev); > if (ret) > - return ret; > + goto err_job_fini; [Severity: High] This isn't a bug introduced by this patch, but does the initialization order risk a bus fault if a spurious interrupt arrives early? In ethosu_probe(), ethosu_job_init() requests and unmasks the IRQ before ethosu_init() is called to enable the device clocks. If a spurious interrupt fires while the device is still powered off (or in autosuspend), the handler executes unconditionally: drivers/accel/ethosu/ethosu_job.c:ethosu_job_irq_handler() { ... u32 status = readl_relaxed(dev->regs + NPU_REG_STATUS); ... } Can reading these unclocked memory-mapped registers cause a synchronous external abort? > > ret = drm_dev_register(ðosudev->base, 0); > if (ret) > - pm_runtime_dont_use_autosuspend(ethosudev->base.dev); > + goto err_pm_runtime; > + > + pm_runtime_put_autosuspend(ethosudev->base.dev); > + return 0; > > +err_pm_runtime: > + pm_runtime_dont_use_autosuspend(ethosudev->base.dev); > pm_runtime_put_autosuspend(ethosudev->base.dev); [Severity: High] This isn't a bug introduced by this patch, but does using pm_runtime_put_autosuspend() here cause a problem with devres cleanup? When the probe function fails and returns, devres will immediately call pm_runtime_disable(). According to the PM subsystem guidelines, using an asynchronous pm_runtime_put() like pm_runtime_put_autosuspend() when pm_runtime_disable() follows immediately causes the pending suspend work to be cancelled. Can this leave the NPU hardware powered on and in an incorrect PM state? > + if (ethosudev->sram) > + gen_pool_free(ethosudev->srampool, (unsigned > long)ethosudev->sram, > + ethosudev->npu_info.sram_size); > +err_job_fini: > + ethosu_job_fini(ethosudev); [Severity: High] This isn't a bug introduced by this patch, but could this error path lead to a use-after-free regression due to the interrupt handler remaining active? In ethosu_job_init(), the hardware interrupt is requested via devm_request_threaded_irq(). Because it is devres-managed, the IRQ is not disabled until after the probe function completely finishes and devres runs. However, ethosu_job_fini() synchronously destroys the DRM scheduler here. If a spurious or delayed interrupt fires in the window between drm_sched_fini() and devres cleanup: drivers/accel/ethosu/ethosu_job.c:ethosu_job_irq_handler() { ... drm_sched_fault(&edev->sched); ... } Will the IRQ handler access the freed scheduler structures? > return ret; > } [Severity: High] This is a pre-existing issue, but does the error path in ethosu_ioctl_submit_job() leak the done_fence allocation? In ethosu_ioctl_submit_job(), ejob->done_fence is dynamically allocated: drivers/accel/ethosu/ethosu_job.c:ethosu_ioctl_submit_job() { ... ejob->done_fence = kzalloc_obj(*ejob->done_fence); ... } If a subsequent step fails (such as drm_gem_object_lookup failing due to an invalid command stream buffer handle), the code jumps to out_cleanup_job. The cleanup function ethosu_job_err_cleanup() frees the job struct and BO references, but it doesn't appear to call kfree() on ejob->done_fence. Could unprivileged userspace trigger this repeatedly to drain kernel memory? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=6
