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 80C3437F8C2; Fri, 7 Aug 2026 15:26:45 +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=1786116406; cv=none; b=pYldulaT/LQcQxBopLtj4aZztTxHKlIzYuAk2P4gjHU3HEmsGh6bUlH1GzwrJrENG3lsTYv4hFDckAJ/1WGAsyxLx+AukbFGvj1jt9G4xdX+N4LW6V7Z/ol7XFajjYymfWCzJq2V5ZI/rdnjH3vYsgCC5yXA+O4xsP+MSR3xg4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786116406; c=relaxed/simple; bh=fBZR9leceW3ptAjV4dnP26mwWabVJkrjcahCvdP42S4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SO6ynHEhP9Znd5qpfvziFLmn6oUwUJrUP/hjbKSBrN3+4GMAYJ4y7nRB5hnibFRju2JZLx0NdHsvBWdld/1dh/U79sdEmQeGDgZTNuoj7vMLuDGPkxPNHDkqrDe8S3JH2e04yLGUH4vxHIMGRnmaygdt6nvkuUi1acIzyTgUHKY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AwhgjsDZ; 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="AwhgjsDZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62FD61F000E9; Fri, 7 Aug 2026 15:26:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786116404; bh=BV5wluZtdcPEEbSzJCx+A00G/Q9k9HbHSM7naLBiVqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AwhgjsDZPw8ehF1I/INk4K+kr4naRshQbq/9rhB2z6G8uC0UN6DpDjIY+P/ZjKGWK gjoBkF9wSmU3NIna4jDsUwPC9YyimWj9CMgKLe38u8S7HlokU/FmLbB0Crxb1fyi4B rO4nCxWWNXhCI5T1j6TWo1MSYSN40UeNH2nU6RP4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Andrei Kuchynski , Benson Leung , Sasha Levin Subject: [PATCH 6.6 221/261] usb: typec: ucsi: Fix race condition and ordering in port unregistration Date: Fri, 7 Aug 2026 16:39:38 +0200 Message-ID: <20260807143420.136962758@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143415.358597922@linuxfoundation.org> References: <20260807143415.358597922@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrei Kuchynski [ Upstream commit 7aa7d4bf9d3fa9a6a47b640ad103ab433b7ff261 ] A synchronization issue exists during port unregistration where pending partner work items can race against workqueue destruction, leading to use-after-free conditions: cros_ec_ucsi cros_ec_ucsi.3.auto: error -ETIMEDOUT: PPM init failed BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:__queue_work+0x83/0x4a0 Call Trace: __cfi_delayed_work_timer_fn+0x10/0x10 run_timer_softirq+0x3b6/0xbd0 sched_clock_cpu+0xc/0x110 irq_exit_rcu+0x18d/0x330 fred_sysvec_apic_timer_interrupt+0x5e/0x80 Fix this by ensuring strict ordering and proper serialization during teardown: 1. Move ucsi_unregister_partner() to the beginning of the teardown sequence and protect it under the connector mutex lock. 2. Ensure all pending partner tasks are explicitly flushed and finished before the workqueue is destroyed. 3. Switch from mod_delayed_work() to a cancel_delayed_work() and queue_delayed_work() sequence. This guarantees that items currently marked as pending won't be scheduled an additional time, preventing a double release of resources which leads to the following crash: Oops: general protection fault, probably for non-canonical address 0xdead000000000122: 0000 [#1] SMP NOPTI Workqueue: cros_ec_ucsi.3.auto-con2 ucsi_poll_worker RIP: 0010:ucsi_poll_worker+0x65/0x1e0 Call Trace: process_scheduled_works+0x218/0x6d0 worker_thread+0x188/0x3f0 __cfi_worker_thread+0x10/0x10 kthread+0x226/0x2a0 To ensure these rules are applied identically across both the normal teardown and the ucsi_init() error paths, consolidate the cleanup logic into a new helper, ucsi_unregister_port(). Cc: stable Fixes: b9aa02ca39a4 ("usb: typec: ucsi: Add polling mechanism for partner tasks like alt mode checking") Fixes: b13abcb7ddd8 ("usb: typec: ucsi: Fix NULL pointer access") Fixes: fac4b8633fd6 ("usb: ucsi: Ensure connector delayed work items are flushed") Signed-off-by: Andrei Kuchynski Reviewed-by: Benson Leung Link: https://patch.msgid.link/20260707141736.1635698-1-akuchynski@chromium.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/ucsi/ucsi.c | 82 +++++++++++++++++++----------------------- 1 file changed, 39 insertions(+), 43 deletions(-) --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -1407,6 +1407,42 @@ out_unlock: return ret; } +static void ucsi_unregister_port(struct ucsi_connector *con) +{ + struct ucsi_work *uwork; + + if (con->wq) { + mutex_lock(&con->lock); + ucsi_unregister_partner(con); + /* + * queue delayed items immediately so they can execute + * and free themselves before the wq is destroyed + */ + list_for_each_entry(uwork, &con->partner_tasks, node) { + if (cancel_delayed_work(&uwork->work)) + queue_delayed_work(con->wq, &uwork->work, 0); + } + mutex_unlock(&con->lock); + + destroy_workqueue(con->wq); + con->wq = NULL; + } else { + ucsi_unregister_partner(con); + } + + ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON); + ucsi_unregister_port_psy(con); + + usb_power_delivery_unregister_capabilities(con->port_sink_caps); + con->port_sink_caps = NULL; + usb_power_delivery_unregister_capabilities(con->port_source_caps); + con->port_source_caps = NULL; + usb_power_delivery_unregister(con->pd); + con->pd = NULL; + typec_unregister_port(con->port); + con->port = NULL; +} + static u64 ucsi_get_supported_notifications(struct ucsi *ucsi) { u8 features = ucsi->cap.features; @@ -1515,22 +1551,8 @@ err_unregister: for (i = 0; i < ucsi->cap.num_connectors; i++) lockdep_unregister_key(&connector[i].lock_key); - for (con = connector; con->port; con++) { - if (con->wq) - destroy_workqueue(con->wq); - ucsi_unregister_partner(con); - ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON); - ucsi_unregister_port_psy(con); - - usb_power_delivery_unregister_capabilities(con->port_sink_caps); - con->port_sink_caps = NULL; - usb_power_delivery_unregister_capabilities(con->port_source_caps); - con->port_source_caps = NULL; - usb_power_delivery_unregister(con->pd); - con->pd = NULL; - typec_unregister_port(con->port); - con->port = NULL; - } + for (con = connector; con->port; con++) + ucsi_unregister_port(con); kfree(connector); err_reset: memset(&ucsi->cap, 0, sizeof(ucsi->cap)); @@ -1756,33 +1778,7 @@ void ucsi_unregister(struct ucsi *ucsi) for (i = 0; i < ucsi->cap.num_connectors; i++) { cancel_work_sync(&ucsi->connector[i].work); - - if (ucsi->connector[i].wq) { - struct ucsi_work *uwork; - - mutex_lock(&ucsi->connector[i].lock); - /* - * queue delayed items immediately so they can execute - * and free themselves before the wq is destroyed - */ - list_for_each_entry(uwork, &ucsi->connector[i].partner_tasks, node) - mod_delayed_work(ucsi->connector[i].wq, &uwork->work, 0); - mutex_unlock(&ucsi->connector[i].lock); - destroy_workqueue(ucsi->connector[i].wq); - } - - ucsi_unregister_partner(&ucsi->connector[i]); - ucsi_unregister_altmodes(&ucsi->connector[i], - UCSI_RECIPIENT_CON); - ucsi_unregister_port_psy(&ucsi->connector[i]); - - usb_power_delivery_unregister_capabilities(ucsi->connector[i].port_sink_caps); - ucsi->connector[i].port_sink_caps = NULL; - usb_power_delivery_unregister_capabilities(ucsi->connector[i].port_source_caps); - ucsi->connector[i].port_source_caps = NULL; - usb_power_delivery_unregister(ucsi->connector[i].pd); - ucsi->connector[i].pd = NULL; - typec_unregister_port(ucsi->connector[i].port); + ucsi_unregister_port(&ucsi->connector[i]); lockdep_unregister_key(&ucsi->connector[i].lock_key); }