Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
Pre-existing issues: - [High] Use-after-free of pfdev->perfcnt in GPU interrupt handler on device unbind due to devres cleanup order. -- commit 62f6a919f812a1a1e64197b8f8a6a6d6f4790287 Author: Adrián Larumbe <[email protected]> drm/panfrost: Move perfcnt GPU disable sequence into a helper This commit factors out the performance counter hardware disable sequence into a new helper function panfrost_perfcnt_hw_disable() to reduce repetition. > diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c > b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c > index 7020c0192e189..f71534e741b65 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c > +++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c > @@ -35,6 +35,16 @@ struct panfrost_perfcnt { > struct completion dump_comp; > }; > > +static void panfrost_perfcnt_hw_disable(struct panfrost_device *pfdev) > +{ > + gpu_write(pfdev, GPU_PERFCNT_CFG, > + GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_OFF)); > + gpu_write(pfdev, GPU_PRFCNT_JM_EN, 0x0); > + gpu_write(pfdev, GPU_PRFCNT_SHADER_EN, 0x0); > + gpu_write(pfdev, GPU_PRFCNT_MMU_L2_EN, 0x0); > + gpu_write(pfdev, GPU_PRFCNT_TILER_EN, 0); > +} > + > void panfrost_perfcnt_clean_cache_done(struct panfrost_device *pfdev) > { > complete(&pfdev->perfcnt->dump_comp); [Severity: High] This isn't a bug introduced by this patch, but can this dereference of pfdev->perfcnt in panfrost_perfcnt_clean_cache_done() lead to a use-after-free during device unbind? The allocation order in panfrost_device_init() establishes a devres LIFO free order that could cause this: panfrost_device.c:panfrost_device_init() { ... err = panfrost_gpu_init(pfdev); // Registers GPU IRQ via devm_request_irq() ... err = panfrost_perfcnt_init(pfdev); // Allocates pfdev->perfcnt via devm_kzalloc() ... } Because devres cleans up in LIFO order, on device unbind, pfdev->perfcnt is freed before the GPU IRQ handler is unregistered. Additionally, panfrost_device_fini() temporarily un-suspends the device, which unmasks the hardware interrupts via panfrost_device_reset(), and then calls panfrost_gpu_fini(). While panfrost_gpu_fini() powers off the hardware, it does not mask the interrupts. If the shared IRQ line fires during this window, or if reading GPU_INT_STAT returns 0xFFFFFFFF because power domains are off, panfrost_gpu_irq_handler() will execute, pass the state & GPU_IRQ_CLEAN_CACHES_COMPLETED check, and call panfrost_perfcnt_clean_cache_done(). Would this result in a use-after-free when accessing pfdev->perfcnt->dump_comp? [ ... ] -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=11
