From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590235; b=cS14aEIYcP/3XP8UrmXztLMK6rxTRxFu1KsCM9FvwZxgIiUSo0yqLAMh6X0i37h1TAHr TE3MXH9W6NwlYDxNd6KrYFHRzPPOEAFeXQ9o9gojpWXGzTg6PBJClCWBwlzqkeZZ+Kjfk IPjki0R1+lDsF+hEwdqjHogicmISAgbLeDukAeMA3XIshzdx9H1e3I9q+xn5K2fVsVEws /3oCGs2+4pgUeto4SjDIpHrC4plJA27YusTu12gfkrJlh0Ld41ZfUvMQ+HxLnbkfQLjeU 98q3B7VfwsHPAhRTelOEv/vpdezdbQE8C0RhCcS+kXnufQ1RvAlcSC3qtT37PR7UgEA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590235; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=cIc8mGcO00u/3nja+Ou8wQXRJUoflazEN4DmvWWyw3A=; b=1QC/1JgICQVEnrFTQTtmVe2nC/I98yPIMWPe9U8nWZNrpiPnEEyYFdtu0BHssfottii1 VViKsdKoKgn3Vn4zTYhjtJ43Fbmfmlugx7ULxXxvsCrX8YjRaXfapEXw2ivmgbvyolGLY ICp9HOopXt6PWKfy5tguZFVPmWT1yuaV6zItAKxitrXa+SxbYwxAitYO8mzLJECZrUP+h byANRMf0s8JjAhu+npkjgieug6bU477n0w6bns8VM76f4JAGP5SentGYQY4rFvcJps6u3 XXG7vL00OXcmFyXogKMv9txPJhdunYdskSAg2CFtwMS04LQfoJf6z2KYsQDikd94HVw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ZyNdFYCO; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB9776075E1D; Fri, 13 Nov 2026 17:17:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ZyNdFYCO Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57DA01F000C5; Fri, 13 Nov 2026 17:17:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590235; bh=cIc8mGcO00u/3nja+Ou8wQXRJUoflazEN4DmvWWyw3A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZyNdFYCOLsynslNCaq7E/XQkBRhqXVDL9OVa8RuGYfVMsP7GTYvaqNQhyOK3kQblv 7A+pwtwygyccszN5sqqNJcGsTO4eSQ2vlWjRmHOGmpltNTS8W9wrrc4miwTnJe3TWE 5lGqS1rU+mvIe3gRtAswLKwbLn8rCs5bGsZIB7L8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hyungjung Joo , Michael Grzeschik , Dominique Martinet , Sasha Levin Subject: [PATCH 6.18 192/686] net/9p/usbg: clear stale client pointer on close Date: Fri, 13 Nov 2026 10:45:25 -0500 Message-ID: <20261113153827.556056853@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hyungjung Joo [ Upstream commit a478958f4c1181ff3362f8857b489c2d069f9c7d ] p9_usbg_close() tears down the client transport, but usb9pfs keeps using usb9pfs->client from asynchronous TX and RX completion handlers. A late completion can therefore dereference a client that has already been freed during mount teardown. Clear usb9pfs->client under usb9pfs->lock when closing the transport, detach any pending TX request from in_req->context, and make the TX/RX completion handlers bail out once the transport has been detached. This keeps late completions from touching a freed or rebound p9_client. Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport") Cc: stable@vger.kernel.org Signed-off-by: Hyungjung Joo Signed-off-by: Michael Grzeschik Message-ID: <20260922-usb9pfsfixes-v1-7-9d8dcc52904c@kernel.org> Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- net/9p/trans_usbg.c | 61 +++++++++++++++++++++++++++++++++------------ 1 file changed, 45 insertions(+), 16 deletions(-) diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c index ed8f01ead839a..938e3130ab81a 100644 --- a/net/9p/trans_usbg.c +++ b/net/9p/trans_usbg.c @@ -148,7 +148,8 @@ static void usb9pfs_tx_complete(struct usb_ep *ep, struct usb_request *req) { struct f_usb9pfs *usb9pfs = ep->driver_data; struct usb_composite_dev *cdev = usb9pfs->function.config->cdev; - struct p9_req_t *p9_tx_req = req->context; + struct p9_client *client; + struct p9_req_t *p9_tx_req; unsigned long flags; /* reset zero packages */ @@ -164,18 +165,25 @@ static void usb9pfs_tx_complete(struct usb_ep *ep, struct usb_request *req) ep->name, req->status, req->actual, req->length); spin_lock_irqsave(&usb9pfs->lock, flags); - WRITE_ONCE(p9_tx_req->status, REQ_STATUS_SENT); + client = usb9pfs->client; + p9_tx_req = req->context; + req->context = NULL; - p9_req_put(usb9pfs->client, p9_tx_req); + if (!client || !p9_tx_req) + goto unlock_complete; - req->context = NULL; + WRITE_ONCE(p9_tx_req->status, REQ_STATUS_SENT); + p9_req_put(client, p9_tx_req); + +unlock_complete: spin_unlock_irqrestore(&usb9pfs->lock, flags); complete(&usb9pfs->send); } -static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf) +static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, + struct p9_client *client, void *buf) { struct p9_req_t *p9_rx_req; struct p9_fcall rc; @@ -201,7 +209,7 @@ static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf) "mux %p pkt: size: %d bytes tag: %d\n", usb9pfs, rc.size, rc.tag); - p9_rx_req = p9_tag_lookup(usb9pfs->client, rc.tag); + p9_rx_req = p9_tag_lookup(client, rc.tag); if (!p9_rx_req || p9_rx_req->status != REQ_STATUS_SENT) { p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", rc.tag); return NULL; @@ -211,7 +219,7 @@ static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf) p9_debug(P9_DEBUG_ERROR, "requested packet size too big: %d for tag %d with capacity %zd\n", rc.size, rc.tag, p9_rx_req->rc.capacity); - p9_req_put(usb9pfs->client, p9_rx_req); + p9_req_put(client, p9_rx_req); return NULL; } @@ -219,7 +227,7 @@ static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf) p9_debug(P9_DEBUG_ERROR, "No recv fcall for tag %d (req %p), disconnecting!\n", rc.tag, p9_rx_req); - p9_req_put(usb9pfs->client, p9_rx_req); + p9_req_put(client, p9_rx_req); return NULL; } @@ -230,8 +238,10 @@ static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req) { struct f_usb9pfs *usb9pfs = ep->driver_data; struct usb_composite_dev *cdev = usb9pfs->function.config->cdev; + struct p9_client *client; struct p9_req_t *p9_rx_req; unsigned int req_size = req->actual; + unsigned long flags; int status = REQ_STATUS_RCVD; if (req->status) { @@ -240,9 +250,16 @@ static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req) return; } - p9_rx_req = usb9pfs_rx_header(usb9pfs, req->buf); - if (!p9_rx_req) + spin_lock_irqsave(&usb9pfs->lock, flags); + client = usb9pfs->client; + if (!client) { + spin_unlock_irqrestore(&usb9pfs->lock, flags); return; + } + + p9_rx_req = usb9pfs_rx_header(usb9pfs, client, req->buf); + if (!p9_rx_req) + goto out_unlock; if (req_size > p9_rx_req->rc.capacity) { dev_err(&cdev->gadget->dev, @@ -256,8 +273,11 @@ static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req) p9_rx_req->rc.size = req_size; - p9_client_cb(usb9pfs->client, p9_rx_req, status); - p9_req_put(usb9pfs->client, p9_rx_req); + p9_client_cb(client, p9_rx_req, status); + p9_req_put(client, p9_rx_req); + +out_unlock: + spin_unlock_irqrestore(&usb9pfs->lock, flags); complete(&usb9pfs->received); } @@ -410,7 +430,9 @@ static int p9_usbg_create(struct p9_client *client, const char *devname, char *a client->status = Disconnected; else client->status = Connected; + spin_lock_irq(&usb9pfs->lock); usb9pfs->client = client; + spin_unlock_irq(&usb9pfs->lock); client->trans_mod->maxsize = usb9pfs->buflen; @@ -421,18 +443,25 @@ static int p9_usbg_create(struct p9_client *client, const char *devname, char *a static void usb9pfs_clear_tx(struct f_usb9pfs *usb9pfs) { + struct p9_client *client; struct p9_req_t *req; + unsigned long flags; - guard(spinlock_irqsave)(&usb9pfs->lock); + spin_lock_irqsave(&usb9pfs->lock, flags); + client = usb9pfs->client; + usb9pfs->client = NULL; + req = usb9pfs->in_req ? usb9pfs->in_req->context : NULL; + if (usb9pfs->in_req) + usb9pfs->in_req->context = NULL; + spin_unlock_irqrestore(&usb9pfs->lock, flags); - req = usb9pfs->in_req->context; - if (!req) + if (!req || !client) return; if (!req->t_err) req->t_err = -ECONNRESET; - p9_client_cb(usb9pfs->client, req, REQ_STATUS_ERROR); + p9_client_cb(client, req, REQ_STATUS_ERROR); usb9pfs->in_req->context = NULL; } -- 2.53.0