On Sat Sep 12 17:29:45 2026 -0700, Xiang Mei wrote:
> em28xx_audio_urb_init() divides by the audio endpoint's wMaxPacketSize
> without checking it, so a USB device that declares a zero-sized audio
> endpoint divides by zero at probe time.
>
> Reject a zero-sized audio endpoint like a missing one; the caller already
> unwinds on a negative return.
>
> Oops: divide error: 0000 [#1] SMP NOPTI
> Workqueue: usb_hub_wq hub_event
> RIP: 0010:em28xx_audio_init (drivers/media/usb/em28xx/em28xx-audio.c:718)
> Call Trace:
> em28xx_init_extension (drivers/media/usb/em28xx/em28xx-core.c:1248)
> em28xx_init_dev.isra.0 (drivers/media/usb/em28xx/em28xx-cards.c:3887)
> em28xx_usb_probe (drivers/media/usb/em28xx/em28xx-cards.c:4258)
> usb_probe_interface (drivers/usb/core/driver.c:396)
> ...
> usb_set_configuration (drivers/usb/core/message.c:2268)
> usb_generic_driver_probe (drivers/usb/core/generic.c:250)
> usb_probe_device (drivers/usb/core/driver.c:291)
> ...
> usb_new_device (drivers/usb/core/hub.c:2703)
> hub_event (drivers/usb/core/hub.c:5961)
> process_one_work (kernel/workqueue.c:3322)
> worker_thread (kernel/workqueue.c:3486)
> 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
>
> Fixes: 1b3fd2d34266 ("[media] em28xx-audio: don't hardcode audio URB
> calculus")
> Cc: [email protected]
> Reported-by: [email protected]
> Closes:
> https://lore.kernel.org/all/51lCz4R7QyTUKbh4mhXNaNzX0evpk0siOzbh%40bugs.sh/
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Xiang Mei <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/usb/em28xx/em28xx-audio.c | 7 +++++++
1 file changed, 7 insertions(+)
---
diff --git a/drivers/media/usb/em28xx/em28xx-audio.c
b/drivers/media/usb/em28xx/em28xx-audio.c
index ccff6be5599e..7f0c5826ce5e 100644
--- a/drivers/media/usb/em28xx/em28xx-audio.c
+++ b/drivers/media/usb/em28xx/em28xx-audio.c
@@ -693,6 +693,13 @@ static int em28xx_audio_urb_init(struct em28xx *dev)
}
ep_size = em28xx_audio_ep_packet_size(udev, ep);
+ if (ep_size == 0) {
+ dev_err(&dev->intf->dev,
+ "Audio endpoint 0x%02x has a zero packet size\n",
+ EM28XX_EP_AUDIO);
+ return -ENODEV;
+ }
+
interval = 1 << (ep->bInterval - 1);
dev_info(&dev->intf->dev,
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