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=1794585439; b=Fw2KqJC4KSYSk4PFC0HQpRjaQqHtD8QvzQw+Q8+3plrAsIq9zdibRle07IE5nX/xREXx hCTkaXkjzbtS5IXEQV1wBw1CmIkA787WJJFakCTohhnromPOW3PiKcrrRAM9sEof65pyv r9K08a72DzTYer6aCjt7pjQnj9PWnt9cdtgpQ44VOixnZJ8CBnI3oyqnGJ1/FQZ1L/2pR AxaRDMvNe4Cd1jlaTCgsjcdrrRpQbi2xUPl76WrfyKLejc1m3/jgXBkgL0bhRS5V/e/U6 zKPi0RhSzB0XPy3Ue/520rHvPGqSyDmEkrM66mVLLWrEPoUyEpSuCyFY3KtKix3kzgQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794585439; 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=iXHyIxt43W1YbCTIcz1kBIqeBnbRyxKupmdPDBEMs7I=; b=qtZqIsJ4GJiZCoHbeS4FDUTx99w1kaHVK75yutqsWy/hFRr+d1wnMcYaiDNwP6unEcVV RIjMacqeqvcbI5InDbJR2zqXktcnzSV4OMbiD36+41i2fZRhfaNoRYaQ81XGUE87zDTPu VPgqgSe+TsJcYYfeOUlQAey4C4nwzeloC1whQvBrrkEuUt4Eoeb9UPtoqOO23Y4zpsjBz PAgYFI9PbVC5KcOSPidZYCkxdviAz0GABAldtTfOaac5qI1mYTdKDP4LmgeURIgbhKQIv BspYfzz7WdWKTl7xNaEhl05H8sjMUTCfXp7ONKouq0KH9EsiTzIeyrUuvTreti7J2Tg== 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=mvyyRtey; 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 689F3606A8B2; Fri, 13 Nov 2026 15:57:19 +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=mvyyRtey Received: by smtp.kernel.org (Postfix) with ESMTPSA id 149C71F000C4; Fri, 13 Nov 2026 15:57:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794585439; bh=iXHyIxt43W1YbCTIcz1kBIqeBnbRyxKupmdPDBEMs7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mvyyRteyl8mqTkvQE8OJb+5UYVSpBvWYoOZHjQbsDaWAc1Ml8ghd4dgxVldV4a9wU Rw7P5FZ7mCiEXZbfB69Kt0pR0QDdnqH1Mfllkhw6yRtjBuJEpsxdr0iaZn+Ybk61wX R5OXDZu4FA/xQeDSPms9Ty/LEhK1NC57D4T/Pcm8= 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 7.3 057/507] net/9p/usbg: clear stale client pointer on close Date: Fri, 13 Nov 2026 10:46:01 -0500 Message-ID: <20261113153755.496358233@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153753.358973689@linuxfoundation.org> References: <20261113153753.358973689@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 7.3-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 2be5abae03aea..7d600e1288a30 100644 --- a/net/9p/trans_usbg.c +++ b/net/9p/trans_usbg.c @@ -149,7 +149,8 @@ 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 */ @@ -165,18 +166,25 @@ 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; @@ -202,7 +210,7 @@ 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; @@ -212,7 +220,7 @@ 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; } @@ -220,7 +228,7 @@ 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; } @@ -231,8 +239,10 @@ 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) { @@ -241,9 +251,16 @@ 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, @@ -257,8 +274,11 @@ 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); } @@ -412,7 +432,9 @@ static int p9_usbg_create(struct p9_client *client, struct fs_context *fc) 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; @@ -423,18 +445,25 @@ static int p9_usbg_create(struct p9_client *client, struct fs_context *fc) 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