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 C227A24BBEB for ; Sun, 19 Jul 2026 14:53:45 +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=1784472826; cv=none; b=sRzn194LQbnSSS24VvfcPfdSPKGq4dcquD6SJjfQl4kix95Tet1EAwyYWAzONWiVvmxUKOxQFu2XK1oTcMSbzjgKT9FpzSxc7iSTV5cjur9XpmYNAikBmKYQt3me1G/P9EdD8sdci2MAtQ2CCwNZEGXf78ZUn4xIPGFhjPILKTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784472826; c=relaxed/simple; bh=LYdgYlPiAVBVZIA9CELxGKKSHN5juHME5MRNF5aMdgo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UykTW554Y3tvu6Gyosuo2c2YQ7EWUUjq7AmJJJfOfwyup9YfDKGKssb9atYzdH1dPDHfpXXKESOrbf4oXwiehlGgUIn2eqax7OyxpTP74wptwrKmMwHyYDkSAbipGZnZwG2M9mVB7aCUra5s1zaOr0cRZ4l56ZvjbdAf7/ocxC0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Po3/lsXJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Po3/lsXJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FDF61F00A3D; Sun, 19 Jul 2026 14:53:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784472825; bh=eBLys2dfRLymAJveOBrLW+IwIPZFYDSZVyeiMLTZEQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Po3/lsXJ1KHSTGdO9t9vCRKEA0sccMjge2JQA87zHdRzMgggSkZZevTl1AKBWCOsX DO6miKpR+tNeGzJ4n+F/Ug6SvI3hzS6TtDU5NxzjJMXrn28SdkAhJk52htbFkdm06l DCmHNy2Clp/1bfQzBYBJwLWR9X5qyzWE3qnZoGVfCARNyRLkmKdTWzckEjOtAFQEwb UOFvHMfnPAZivZfV+DS1ESoX/jUVX/UabYvut+T6sBE1hWGFAjP6KGegtzO9kvgei0 XjQabsMIuMXbraBOmVVHeSNV9faH87279o/GmW13rM/nUFc8JlqKpD2Drpy4/k1EaV Filzruy1pSW1Q== From: Sasha Levin To: stable@vger.kernel.org Cc: Xu Rao , stable , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.10.y 2/2] usb: gadget: f_printer: take kref only for successful open Date: Sun, 19 Jul 2026 10:53:42 -0400 Message-ID: <20260719145342.5397-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260719145342.5397-1-sashal@kernel.org> References: <2026071412-epilepsy-clerk-af1b@gregkh> <20260719145342.5397-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Xu Rao [ Upstream commit 30adce93d5c4a5a1ec29d9249e3fdfcc391d406b ] printer_open() returns -EBUSY when the character device is already open, but it increments dev->kref regardless of the return value. VFS does not call ->release() for a failed open, so every rejected second open permanently leaks one reference. Move kref_get() into the successful-open branch. Fixes: e8d5f92b8d30 ("usb: gadget: function: printer: fix use-after-free in __lock_acquire") Cc: stable Signed-off-by: Xu Rao Link: https://patch.msgid.link/80295742B820DA9B+20260626064617.4090626-1-raoxu@uniontech.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_printer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index 8a65094c421e3b..473206c0362d47 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -358,12 +358,11 @@ printer_open(struct inode *inode, struct file *fd) ret = 0; /* Change the printer status to show that it's on-line. */ dev->printer_status |= PRINTER_SELECTED; + kref_get(&dev->kref); } spin_unlock_irqrestore(&dev->lock, flags); - kref_get(&dev->kref); - return ret; } -- 2.53.0