From b74cedac643b02aefa7da881b58a3792859d9748 Mon Sep 17 00:00:00 2001 From: Xulin Sun Date: Thu, 4 Dec 2025 17:41:53 +0800 Subject: [PATCH] media: chips-media: wave5: Fix device cleanup order to prevent kernel panic Move video device unregistration to the beginning of the remove function to ensure all video operations are stopped before cleaning up the worker thread and disabling PM runtime. This prevents hardware register access after the device has been powered down. In polling mode, the hrtimer periodically triggers wave5_vpu_timer_callback() which queues work to the kthread worker. The worker executes wave5_vpu_irq_work_fn() which reads hardware registers via wave5_vdi_read_register(). The original cleanup order disabled PM runtime and powered down hardware before unregistering video devices. When autosuspend triggers and powers off the hardware, the video devices are still registered and the worker thread can still be triggered by the hrtimer, causing it to attempt reading registers from powered-off hardware. This results in a bus error (synchronous external abort) and kernel panic. This causes random kernel panics during encoding operations: Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP Modules linked in: wave5 rpmsg_ctrl rpmsg_char ... CPU: 0 UID: 0 PID: 1520 Comm: vpu_irq_thread Tainted: G M W pc : wave5_vdi_read_register+0x10/0x38 [wave5] lr : wave5_vpu_irq_work_fn+0x28/0x60 [wave5] Call trace: wave5_vdi_read_register+0x10/0x38 [wave5] kthread_worker_fn+0xd8/0x238 kthread+0x104/0x120 ret_from_fork+0x10/0x20 Code: aa1e03e9 d503201f f9416800 8b214000 (b9400000) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: synchronous external abort: Fatal exception Fixes: 9707a6254a8a ("media: chips-media: wave5: Add the v4l2 layer") Cc: stable@vger.kernel.org Signed-off-by: Xulin Sun Reviewed-by: Nicolas Dufresne Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil --- drivers/media/platform/chips-media/wave5/wave5-vpu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu.c b/drivers/media/platform/chips-media/wave5/wave5-vpu.c index 0bcd48df49d0f..77d6c934d0b9d 100644 --- a/drivers/media/platform/chips-media/wave5/wave5-vpu.c +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu.c @@ -351,6 +351,10 @@ static void wave5_vpu_remove(struct platform_device *pdev) { struct vpu_device *dev = dev_get_drvdata(&pdev->dev); + wave5_vpu_enc_unregister_device(dev); + wave5_vpu_dec_unregister_device(dev); + v4l2_device_unregister(&dev->v4l2_dev); + if (dev->irq < 0) { hrtimer_cancel(&dev->hrtimer); kthread_cancel_work_sync(&dev->work); @@ -364,9 +368,6 @@ static void wave5_vpu_remove(struct platform_device *pdev) mutex_destroy(&dev->hw_lock); reset_control_assert(dev->resets); clk_bulk_disable_unprepare(dev->num_clks, dev->clks); - wave5_vpu_enc_unregister_device(dev); - wave5_vpu_dec_unregister_device(dev); - v4l2_device_unregister(&dev->v4l2_dev); wave5_vdi_release(&pdev->dev); ida_destroy(&dev->inst_ida); } -- 2.47.3