From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6EBB04B2CC2 for ; Thu, 3 Sep 2026 14:15:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788444946; cv=none; b=oXEd8a3slXwy9uJewVF6melE5rc8na2fMLjPNoXSkU6OpAamSm9SABig1ksn/eOQ+Ni8jdzIufKWzkatmZMtjHzWq/m+LWgNvpsniemnEMRmyA4gJ4okq4nWOI6rFs4eMcSeYk73uh3THc++Ux5vdh4T6eua4oWn9WkLoAf7x14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788444946; c=relaxed/simple; bh=URWsQI1MfVyDQmfrPm40dfNfroKIxeVXz+2Uk/wxcAc=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=B/ocj+2AuoHBDQLkFFHH4DV9n/0XYQVJRdhPHiCa6C4dmVXFAS26lOf1r0tiVB/aNE5XtB7HdOHLZSKhch8K3ncmbTaw04WAzC6GbzTcFjTOBiYdwGjXjLhWdnlN/p7QqHg9AhdeUch6+q7JETCpsHyf/jnxcIVdzeL2VcPj6es= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LB4B+tBX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LB4B+tBX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF74E1F00A3F; Thu, 3 Sep 2026 14:15:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788444929; bh=klQ5AwPdzejipvhBMB4Lw9cD8zGQHEukzDqpb2T3LuQ=; h=Subject:To:Cc:From:Date; b=LB4B+tBXZs4M2iHaarDeOFY44w3yk3Z3YNI4lXO9CKPt7N835Ckdy6WKNuA4yoWiX K9ahG5EFV9MyGD+eCYeI9ZmRClMJRbfAgSu5VgJrYJqIEbQXz2BSkYM0dHcyAucH8V wl3mNgq32dyFHYQjhPVfjDNoTA7OFOgxyVgVrpaE= Subject: FAILED: patch "[PATCH] Bluetooth: hci_core: use skb_get() instead of skb_clone() for" failed to apply to 6.1-stable tree To: xin.chen2@oss.qualcomm.com,luiz.von.dentz@intel.com Cc: From: Date: Thu, 03 Sep 2026 15:55:31 +0200 Message-ID: <2026090331-cheddar-preheated-6153@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 f5afdff569a09d1cb8cf19826199d024725576cb # git commit -s git send-email --to '' --in-reply-to '2026090331-cheddar-preheated-6153@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f5afdff569a09d1cb8cf19826199d024725576cb Mon Sep 17 00:00:00 2001 From: Xin Chen Date: Wed, 19 Aug 2026 21:53:21 +0800 Subject: [PATCH] Bluetooth: hci_core: use skb_get() instead of skb_clone() for req_skb BT enable fails intermittently with -ETIMEDOUT (-110). The kernel log shows the HCI Read Local Version command was sent and the firmware replied with status 0x00 (logged by hci_req_cmd_complete() BT_DBG), but the waiter in __hci_cmd_sync_sk() never woke up and timed out after 10 s: bluetooth hci0: Opcode 0xfc00 // __hci_cmd_sync_sk bluetooth hci0: opcode 0xfc00 plen 1 // hci_cmd_sync_add bluetooth hci0: skb len 4 // hci_cmd_sync_alloc bluetooth hci0: length 1 // hci_req_sync_run Bluetooth: hci0 cmd_cnt 1 cmd queued 1 // hci_cmd_work Bluetooth: hci0 type 1 len 4 // hci_send_frame Bluetooth: opcode 0xfc00 status 0x00 // hci_req_cmd_complete <-- req_skb NULL: req_complete_skb not set, hci_cmd_sync_complete() never called, req_status stays HCI_REQ_PEND --> <-- 10 s later: wait_event_interruptible_timeout expires --> bluetooth hci0: end: err -110 // __hci_cmd_sync_sk The root cause is that hci_send_cmd_sync() clones the sent command into hdev->req_skb so that hci_req_cmd_complete() can locate the registered completion callback. Under memory pressure this skb_clone() fails, leaving hdev->req_skb NULL. The firmware reply is received and processed, but hci_req_cmd_complete() finds NULL req_skb, so hci_cmd_sync_complete() is never called, req_status stays HCI_REQ_PEND, and the waiter times out with -ETIMEDOUT. req_skb is only used to read bt_cb(skb)->hci callbacks and opcode -- it is never modified. Replace skb_clone() with skb_get(), which simply increments the reference count of hdev->sent_cmd without allocating new memory and therefore cannot fail. This issue was first observed as a use-after-free in ttyport_close() when ttyport_open() failed, which was investigated in an earlier patch series [1]. That investigation led to the discovery of the true root cause described above. [1] https://lore.kernel.org/all/20250430111617.1151390-1-quic_cxin@quicinc.com/ Fixes: 2615fd9a7c25 ("Bluetooth: hci_sync: Fix overwriting request callback") Cc: stable@vger.kernel.org Signed-off-by: Xin Chen Signed-off-by: Luiz Augusto von Dentz diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 509c820a693d..35a1be57e386 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -4093,7 +4093,7 @@ static int hci_send_cmd_sync(struct hci_dev *hdev, struct sk_buff *skb) if (READ_ONCE(hdev->req_status) == HCI_REQ_PEND && !hci_dev_test_and_set_flag(hdev, HCI_CMD_PENDING)) { kfree_skb(hdev->req_skb); - hdev->req_skb = skb_clone(hdev->sent_cmd, GFP_KERNEL); + hdev->req_skb = skb_get(hdev->sent_cmd); } return err;