From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE7C82DEA75 for ; Wed, 8 Apr 2026 11:56:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775649418; cv=none; b=AWFs+MBXs7RHNeS8w+K+7eu3COUr3QUJNo7eFcfGHVDav9amneJfJylwh6hHqmM2J64TkGDc5T9+xSbbNI0CGYX04ImOJ/RrskgT9MLC9JDmdT559cOMr0Olmn052w52R7CnedSb17JMg9g8/U4+PQerP9vqzhrffcpc4hkEQGk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775649418; c=relaxed/simple; bh=YCVkBQKet0fn5YpxlU1qnYgA0IuassMVVi4iu8E2RvI=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=mX3GUcXwnjv1hVGn8pUYDz0kXZKttCH8Q044VYDnK3NBICXJLYPEe9WVq0o1YYzdfrHQXddlRVOPApflEmZmztSc9RL6R94a5QGs2v+JSuBGX/A+ZrF+oTv3rUGAn47gHt7FxEBVOzhYJYY0KaZ/svpJKMwhZtNeC5mBmN5mAMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hvnfZPJa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hvnfZPJa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E943C19421; Wed, 8 Apr 2026 11:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775649418; bh=YCVkBQKet0fn5YpxlU1qnYgA0IuassMVVi4iu8E2RvI=; h=Subject:To:Cc:From:Date:From; b=hvnfZPJaz3x3P3F6m1y1nxbc7QXl89DPi++QrlA8nQYbnbAbt3CWSpyeamr5g5nKe kUbScuB64k88B5T9Sz3DdbbYIBEIc0fnfp23ollsUtCi/bZkUTaP+zYRFkciM/vxTl ZU1VvOwwm6sHj1TH1EjEJEePbLUhqRyXyHrbNSUI= Subject: FAILED: patch "[PATCH] usb: gadget: u_ether: Fix race between gether_disconnect and" failed to apply to 6.1-stable tree To: khtsai@google.com,gregkh@linuxfoundation.org,stable@kernel.org Cc: From: Date: Wed, 08 Apr 2026 13:56:56 +0200 Message-ID: <2026040856-salutary-stress-ecc2@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-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 . 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-6.1.y git checkout FETCH_HEAD git cherry-pick -x e1eabb072c75681f78312c484ccfffb7430f206e # git commit -s git send-email --to '' --in-reply-to '2026040856-salutary-stress-ecc2@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e1eabb072c75681f78312c484ccfffb7430f206e Mon Sep 17 00:00:00 2001 From: Kuen-Han Tsai Date: Wed, 11 Mar 2026 17:12:15 +0800 Subject: [PATCH] usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop A race condition between gether_disconnect() and eth_stop() leads to a NULL pointer dereference. Specifically, if eth_stop() is triggered concurrently while gether_disconnect() is tearing down the endpoints, eth_stop() attempts to access the cleared endpoint descriptor, causing the following NPE: Unable to handle kernel NULL pointer dereference Call trace: __dwc3_gadget_ep_enable+0x60/0x788 dwc3_gadget_ep_enable+0x70/0xe4 usb_ep_enable+0x60/0x15c eth_stop+0xb8/0x108 Because eth_stop() crashes while holding the dev->lock, the thread running gether_disconnect() fails to acquire the same lock and spins forever, resulting in a hardlockup: Core - Debugging Information for Hardlockup core(7) Call trace: queued_spin_lock_slowpath+0x94/0x488 _raw_spin_lock+0x64/0x6c gether_disconnect+0x19c/0x1e8 ncm_set_alt+0x68/0x1a0 composite_setup+0x6a0/0xc50 The root cause is that the clearing of dev->port_usb in gether_disconnect() is delayed until the end of the function. Move the clearing of dev->port_usb to the very beginning of gether_disconnect() while holding dev->lock. This cuts off the link immediately, ensuring eth_stop() will see dev->port_usb as NULL and safely bail out. Fixes: 2b3d942c4878 ("usb ethernet gadget: split out network core") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260311-gether-disconnect-npe-v1-1-454966adf7c7@google.com Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 1a9e7c495e2e..23c7c0cdf202 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -1223,6 +1223,11 @@ void gether_disconnect(struct gether *link) DBG(dev, "%s\n", __func__); + spin_lock(&dev->lock); + dev->port_usb = NULL; + link->is_suspend = false; + spin_unlock(&dev->lock); + netif_stop_queue(dev->net); netif_carrier_off(dev->net); @@ -1260,11 +1265,6 @@ void gether_disconnect(struct gether *link) dev->header_len = 0; dev->unwrap = NULL; dev->wrap = NULL; - - spin_lock(&dev->lock); - dev->port_usb = NULL; - link->is_suspend = false; - spin_unlock(&dev->lock); } EXPORT_SYMBOL_GPL(gether_disconnect);