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 C3F3B2FDC20 for ; Mon, 5 Oct 2026 20:17:07 +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=1791231428; cv=none; b=g/szDM2AM6LwF2bXi1w7DBXwixS5QCkIhOdLOk4sxIuJhrnjiyePsuXXXmAwHwzmf37Omsok7dKOqV/OjmRXuImSTRbDXxgW3zzImwPtqwvQeydx1V1FMyE3qdbiEUivKuABzsJgHvzbmn1OGnZ96Xcd8B1SQ4HbuJ24GBEVkqo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791231428; c=relaxed/simple; bh=zXvLgT337rvdyhJV23oSLkq2vxVPgXn1+uFIz5NiOz4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=h3B5C5Vc3dBShHEZ0m6LEf5io1pJ7UjN0O6Fim2C7JysR2HA/PlVeiZRaG33sVSrvC2NSVhEHnXBXGvlFNcZabmjz1mK8upYShyujl50mW50QwuU+ueZiSms8PBkqlsQcu72Xs2oGwCYHBcHSsYQ93SNck0+lmYnMvffRsGW1TU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ey93kykc; 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="Ey93kykc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E02BF1F00893; Mon, 5 Oct 2026 20:17:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791231427; bh=u4lcUK/tKyWTX/8uqfvu6meoPFJi1m1qYEjbS5qzWds=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ey93kykcCym3GLhNR8yT/Tl9R2QVsoEZH2eV0W8Zu2ZlPhYXSw6A4QwlaPzp5KF3f T4TaavhsCVamJ8K5HygzBYwBWtDgZQdzrZFPJq6fbY7QrNPQApE8VOPjI/t8yQ96MH ZEUYIXolelRJGgDqaiBOBzmrDNU6tDEX+0gPBMeYc4MSf/0Py2R+gBAtVzyoyegOvn Y1vlt+Gi71DH6TfRlGBAjea5nloaDqmGeppZkrFtWV4Kk+xtzeyYgtWb16hJjiZcVz /EIM76HYuPzIPfap77ozuK0+vMetGOiuf7b7P0d0nVf3z6+hX323RfDaEaM2ia7FSn /zfc7h/sMtpMQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Johan Hovold , stable , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.6.y] tty: tty_port: restore TTY_IO_ERROR on activation failure Date: Mon, 5 Oct 2026 16:17:03 -0400 Message-ID: <20261005201531.3157671-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100521-halogen-alphabet-2d56@gregkh> References: <2026100521-halogen-alphabet-2d56@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Johan Hovold [ Upstream commit 56964f6a31238fb41d5830bb42520c5b10ff7d8f ] 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 # 2.6.33 Signed-off-by: Johan Hovold Link: https://patch.msgid.link/20260908084000.218528-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman [ sashal: Adapted to existing explicit mutex unlocking instead of automatic cleanup. ] Signed-off-by: Sasha Levin --- drivers/tty/tty_port.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index 21430e64b4128..7ee96882e0e48 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -781,6 +781,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty, int retval = port->ops->activate(port, tty); if (retval) { + set_bit(TTY_IO_ERROR, &tty->flags); mutex_unlock(&port->mutex); return retval; } -- 2.53.0