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=1794591012; b=oP6JF4Uwz9+qu+qR+GKf2qHAQOZnLewoZL0JO4xjwvkNpxaA1BzGezPqLlSZBRcsWaL7 bFPWk6rkYNcHXpFgcEKo05rgcvJ53qFnFzI3S2tOzPFX7aHv4ICcS50Mmk2/VQFle1Akl 7YJ1d6JQX4NHdeeK8CqENvxfuxQSXrXPZFnjBO8jR/jf1wtHLcSrQ0NDplAGQjUBbA2by VxJxgv/J+LmufWlwlL4OJG39+UBcYVs4sMMX1tpskxLtCcElUjpJFYOijpZ87NFase4Rc 9041PgixyI/52/3tW2J1Vks4eCV09ePwBXsTCJ0IwYsDDsDKTtRsP7s/aIKFQfj/XHg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591012; 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=LFXFUhiRVqyuv23HXCJf2rPJDDcj4l7SmaJQvMsehlg=; b=bL30xquQGaTpBB0Hx6varL9ITvDTPu8jsogeWmrVtnsb7LaRb1eSlcXWnPgjpKomFuSP d+4We3GwjD2+H3znrZmLnZAoDglE2Yh1WnXNOFcgnhUvWEWEDmAjLvbCxc/QiefeO7p3w 1Mu3PjRctl33I8OQf7Nm63GNChIiX0LoOffpoSGZQKH6Hrhanwzm5TGvD/CREHHbdPOQY 756t0VpTZJGA/v5EcloC2CHWotRvyDVp/hBGx6Db968TQ7dhjFnXU8D/M0i53pgs3HObs XnTdiWsoyQLmn3BbXdkuM+DdDA5FpYkDRxrnmwdqecjcxG+i+xnO2IZ794gRHA1Q1Kg== 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=GGgpHlHC; 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 A26236070F1B; Fri, 13 Nov 2026 17:30:12 +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=GGgpHlHC Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E5271F000C4; Fri, 13 Nov 2026 17:30:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591012; bh=LFXFUhiRVqyuv23HXCJf2rPJDDcj4l7SmaJQvMsehlg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GGgpHlHCLBldo1bLd5hVbPHw/iOs72PNf3trF5P+CD51OeOZJcCxhasmNylK8tiFG 6RkprdQ/7Z4vz4kZhUrLF09SgjfynItU+1KZKUBqiZTOvaP97P+Q0ThkZgvj1C1Ti/ EHdmjDlingcp/Yqbgg55VSkz7Pe24JCQlnAFR28I= 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 6.12 181/670] net/9p/usbg: clear stale client pointer on close Date: Fri, 13 Nov 2026 10:45:45 -0500 Message-ID: <20261113153818.166011861@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@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 6.12-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