FAILED: patch "[PATCH] media: streamzap: fix race between device disconnection and" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x f656cfbc7a293a039d6a0c7100e1c846845148c1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025040825-taunt-stencil-d364@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f656cfbc7a293a039d6a0c7100e1c846845148c1 Mon Sep 17 00:00:00 2001
From: Murad Masimov <[email protected]>
Date: Mon, 13 Jan 2025 13:51:30 +0300
Subject: [PATCH] media: streamzap: fix race between device disconnection and
urb callback

Syzkaller has reported a general protection fault at function ir_raw_event_store_with_filter(). This crash is caused by a NULL pointer dereference of dev->raw pointer, even though it is checked for NULL in the same function, which means there is a race condition. It occurs due to the incorrect order of actions in the streamzap_disconnect() function:
rc_unregister_device() is called before usb_kill_urb(). The dev->raw pointer is freed and set to NULL in rc_unregister_device(), and only after that usb_kill_urb() waits for in-progress requests to finish.

If rc_unregister_device() is called while streamzap_callback() handler is not finished, this can lead to accessing freed resources. Thus rc_unregister_device() should be called after usb_kill_urb().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

index 9b209e687f25..2ce62fe5d60f 100644
@@ -385,8 +385,8 @@ static void streamzap_disconnect(struct usb_interface *interface)
 	if (!sz)
 		return;
 
-	rc_unregister_device(sz->rdev);
 	usb_kill_urb(sz->urb_in);
+	rc_unregister_device(sz->rdev);
 	usb_free_urb(sz->urb_in);
 	usb_free_coherent(usbdev, sz->buf_in_len, sz->buf_in, sz->dma_in);