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 3F56A4F054D; Tue, 13 Oct 2026 12:21:44 +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=1791894105; cv=none; b=s7JHiMiOlvCQejbLceXMIrnFLeksGUFfvdoDRe+UfZDkAgNUiF9Kk8xJ4Lf+XJ0Of7D+2/mj3gUIqMS0we0jUs1lk6R2AYCkhvpKKDJpm9Ht8RfoxjwhSl0FpBBeRa8BgCK/LR3P1ZRjwacChTLrU/ZpOtGFVniZddmR8XfMWRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791894105; c=relaxed/simple; bh=hvnpPQHdha4iW2Rn8i83ibPVzBZaZZXnfevtC+lQ5Rk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FDSjzD1YcjhLxTdoR/JGLN6XVbg06SACKRvHRp2wOgFpDxNMAdoefRGffsNWse0a8MfNsY02iiFeO/lfjWeBqWHIrEfnO2DZ4vE9YNk3+PQKXY/X1kfwKZkE4nL3jpBQ9Rm+13sKYYGE/cHqjXR0uA/yCGBalXkWkm/uP5VnYp0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=I+M6Y3mo; 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="I+M6Y3mo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82E091F000FF; Tue, 13 Oct 2026 12:21:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791894104; bh=bJOOV8NLmtuH3V9Oao2tiqPChj5X18JtQbW3E6tt+cg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=I+M6Y3mobZJog77bTWigGq+4VbSHPZQ9aOD0bPPnFirEd9h5h13oEG+2qUcWCl/WF jTtCplp8JRE5mWXBlFs7/mj0ecC7Bb+5QDRgtpeNF0EnBe8kl7cYJDcWVFeFWjmdJJ tGo+5tANIrcre6I1apecRDzRcVdaKQg1pPSEquzI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , Sasha Levin Subject: [PATCH 6.18 449/621] tty: skip cdev_del() when no cdev is registered Date: Tue, 13 Oct 2026 13:37:24 +0200 Message-ID: <20261013112931.486728383@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter [ Upstream commit c3b5623fd97648f2747444aa8932ae604662df93 ] TTY device registration can fail before a cdev is allocated. Serial core keeps the port so setserial can still use it, and later removal passes the NULL cdev slot to cdev_del(), causing a NULL-pointer dereference. Only delete the cdev when the slot is not NULL. Fixes: a3a10ce3429e ("Avoid usb reset crashes by making tty_io cdevs truly dynamic") Fixes: da4c279942b0 ("serial: enable serdev support") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Link: https://patch.msgid.link/20260731181844.11330-4-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/tty_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index dd7231d9cab96..07e6bf5f8c6ff 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3327,7 +3327,7 @@ EXPORT_SYMBOL_GPL(tty_register_device_attr); void tty_unregister_device(struct tty_driver *driver, unsigned index) { device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index); - if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { + if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) && driver->cdevs[index]) { cdev_del(driver->cdevs[index]); driver->cdevs[index] = NULL; } -- 2.53.0