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 1CD23370D56; Tue, 8 Sep 2026 08:40:48 +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=1788856850; cv=none; b=qMvr1yd+1PkPMmYABVXyYancg/7brPXfcutHnXxMvjWGd3kQ2uQXnqAXZ1hWFw3+nl1nIdzJc0L5ncij9e3ndqyAR5BhrBp0/fL8Fcn+Yho1v3amzMVLNqLPmL75d4RdDr54AqpJK03RmHgMNe6vFuuwlLciM+k47XZJWZbyGKY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788856850; c=relaxed/simple; bh=Vrfr7zzEwJQEzZ6zaoaVGnzBmprSB9I9ol5Uhw6aLiY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RVRiMeGG/qgRVejLrJPr1nJTtYWeAL0nnHyYc3rwsiTUeAgqJSRAvme8b39fVCjWd0ChcdTxx7cOERSrclGZb6lG7EsE6Po9u6Lny4iWs5HVHk/wzfF3xuHWM6gtNDRailN2ZD6goc/Fv53aTFyYV7xVLa3tL9RIo56QERMqx5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZlqqDKr4; 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="ZlqqDKr4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41CD01F00A3A; Tue, 8 Sep 2026 08:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788856848; bh=lfq8Fegv4esMs1vY+nfswJ3ke6lOATunr4YBcpYS5h0=; h=From:To:Cc:Subject:Date; b=ZlqqDKr4S7WJiCUdcsb9ZAsQNLwkw63A124ROPrQKMGTpRsZDTMnH5nnOj9Ycg8GS wK3BxKThX+QFlzR0qp9zdBdmydTV6HuIwQJIyiMDAWZfUiKa/H8YKW9X4WVKRVgp1z KRwjbi/oX39At6pIP+92QhxiakkiXnORDDbCPH+uMaZ73CRFbij8t/yJoZ20vOD+re 8QZ4GJBryTt/4W0JHlRZNTfpwlZsH+ijkOYYzph8WS6H8g2GtKCe+Nb1sJ8vSZlLpV NIQBOqbQZ5X9vUFmTyCLUya4+oSrdD+Wwds6BHxJ6K9tTa3PmfAUosJlzH+CcjCE3F a+I+ND0wcFywQ== Received: from johan by xi.lan with local (Exim 4.99.4) (envelope-from ) id 1x3rNl-00000000urb-3q1o; Tue, 08 Sep 2026 10:40:45 +0200 From: Johan Hovold To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org Subject: [PATCH] tty: tty_port: restore TTY_IO_ERROR on activation failure Date: Tue, 8 Sep 2026 10:40:00 +0200 Message-ID: <20260908084000.218528-1-johan@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Make sure to restore the TTY_IO_ERROR flag if activation fails to prevent I/O attempts on a port that is gone or powered down. This specifically avoids issues like kernel panic due to unclocked accesses or NULL-pointer dereferences when accessing powered down or deregistered ports when a TTY ioctl races with hangup and open. Note that the flag is set again in tty_port_close() but not restoring it on activation failure leaves a window where drivers fail to handle the ioctl-hangup race. Fixes: a9a37ec33a1b ("tty: tty_port: Move the IO_ERROR clear") Cc: stable@vger.kernel.org # 2.6.33 Signed-off-by: Johan Hovold --- drivers/tty/tty_port.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index 54359310e293..ae33987207b6 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -767,8 +767,10 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty, clear_bit(TTY_IO_ERROR, &tty->flags); if (port->ops->activate) { int retval = port->ops->activate(port, tty); - if (retval) + if (retval) { + set_bit(TTY_IO_ERROR, &tty->flags); return retval; + } } tty_port_set_initialized(port, true); } -- 2.55.0