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 E2E5034B1A6; Tue, 21 Jul 2026 21:49:49 +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=1784670591; cv=none; b=VorxMK4B3DIvXzeDp5/a0CFWUZgO+bEXKIyfC0lGWX1Aj6cRAG+kBoiMcNflekgRt1jfgfvBvxEQuzaBGaK0uZtSIXk7T3yJjPWdNGUar+hkngJzTSmvGPRSKMg3kmUZBos0vmT/MAI4NArr0VoMOgnXrAxhsDh4KovABSPJ8sM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784670591; c=relaxed/simple; bh=nrxypfCbI0svr3SsEGM6sNRXlcidWNg9eO0HNoOCnVs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lSzqBOrEjdgTbCCM4nyoNuafciL6FIYvTwoaQ3TCrv/btNEtVLegI6FO6BBvXB0SUfIeg9W1TOVZVVNX9wzdCkOua+SQ3sLZid8UNdRPl+7R5DG5p9zAlAhwhEjNkK5E9eCrT4KjHA3ElNV1acvLz5T6DebmtzGIrbdYaLGD2VI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Jg772aNN; 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="Jg772aNN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F3B31F000E9; Tue, 21 Jul 2026 21:49:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784670589; bh=1e7406QbpfjrSXNDuwYrzea8FbkaRkLAH3d7hvG/13o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Jg772aNNiAVPT2L9mllljKG+zW79mqMfBoSdzqaoyv0cAcFvoN7xHrcRGZUvb5Uwj BQd5piOg8iAtRN7SPoiS2iRCzi3sl/veQU84u0RAvLkPTgmJFz/wimt5WNdWVkTrd+ AXHxsYkR6V7ZJtltB+V9+stj9BZ/4bz6OihaHA3w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Runyu Xiao , Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 6.1 0991/1067] Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock Date: Tue, 21 Jul 2026 17:26:32 +0200 Message-ID: <20260721152446.728472237@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Runyu Xiao [ Upstream commit 2641a9e0a1dd4af2e21995470a21d55dd35e5203 ] l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for pending_rx_work. process_pending_rx() takes the same mutex, so teardown can deadlock against the worker it is flushing. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the l2cap_conn_ready() -> queue_work(..., &conn->pending_rx_work) submit path, the l2cap_conn_del() -> cancel_work_sync(&conn->pending_rx_work) teardown path, and the process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep reported: WARNING: possible circular locking dependency detected process_pending_rx+0x21/0x2a [vuln_msv] l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv] *** DEADLOCK *** Cancel pending_rx_work before taking conn->lock, matching the existing lock-before-drain ordering used for the two delayed works in the same teardown path. The pending_rx queue is still purged after the work has been cancelled and conn->lock has been acquired. Fixes: 7ab56c3a6ecc ("Bluetooth: Fix deadlock in l2cap_conn_del()") Cc: stable@vger.kernel.org Signed-off-by: Runyu Xiao Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/l2cap_core.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -1785,17 +1785,11 @@ static void l2cap_conn_del(struct hci_co cancel_delayed_work_sync(&conn->info_timer); cancel_work_sync(&conn->id_addr_update_work); + cancel_work_sync(&conn->pending_rx_work); + kfree_skb(conn->rx_skb); skb_queue_purge(&conn->pending_rx); - - /* We can not call flush_work(&conn->pending_rx_work) here since we - * might block if we are running on a worker from the same workqueue - * pending_rx_work is waiting on. - */ - if (work_pending(&conn->pending_rx_work)) - cancel_work_sync(&conn->pending_rx_work); - ida_destroy(&conn->tx_ida); l2cap_unregister_all_users(conn);