7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei commit 2eacf058d2dbb0ae3aaf576459da9e5f2b6bbfbd upstream. go7007_register_encoder() sets go->audio_enabled before calling go7007_snd_init() and discards its return value. go7007_snd_init() assigns go->snd_context only on success, so a failed ALSA setup leaves audio_enabled set with snd_context still NULL. The disconnect path tests audio_enabled and calls go7007_snd_remove(), which dereferences snd_context unconditionally. go7007_snd_init() returns -ENODEV once its never-decremented static card counter reaches SNDRV_CARDS, so SNDRV_CARDS attach/detach cycles arm the next attach; no memory pressure is needed. Set go->audio_enabled only once go7007_snd_init() has succeeded. Oops: general protection fault, probably for non-canonical address ... KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] Workqueue: usb_hub_wq hub_event RIP: 0010:go7007_snd_remove (drivers/media/usb/go7007/snd-go7007.c:273) Call Trace: go7007_usb_disconnect (drivers/media/usb/go7007/go7007-usb.c:1336) usb_unbind_interface (drivers/usb/core/driver.c:461) device_remove (drivers/base/dd.c:618) device_release_driver_internal (drivers/base/dd.c:1349) bus_remove_device (drivers/base/bus.c:664) device_del (drivers/base/core.c:3965) usb_disable_device (drivers/usb/core/message.c:1478) usb_disconnect hub_event (drivers/usb/core/hub.c:5966) process_one_work (kernel/workqueue.c:3396) worker_thread (kernel/workqueue.c:3560) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Kernel panic - not syncing: Fatal exception Cc: stable@vger.kernel.org Fixes: 866b8695d67e ("Staging: add the go7007 video driver") Assisted-by: LLM Signed-off-by: Xiang Mei Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/go7007/go7007-driver.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/media/usb/go7007/go7007-driver.c +++ b/drivers/media/usb/go7007/go7007-driver.c @@ -306,10 +306,9 @@ int go7007_register_encoder(struct go700 if (ret < 0) goto err_free_controls; - if (go->board_info->flags & GO7007_BOARD_HAS_AUDIO) { + if ((go->board_info->flags & GO7007_BOARD_HAS_AUDIO) && + go7007_snd_init(go) == 0) go->audio_enabled = 1; - go7007_snd_init(go); - } return 0; err_free_controls: