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 449233AA9E2 for ; Mon, 5 Oct 2026 20:54:46 +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=1791233689; cv=none; b=iMjb1GPmy0TWO62LLxvNhUtyQPGcEdixJeq6nhFmRVmowFkEQJkvOszmFbb6waX81lDOMiqgDMiq3OfFpPujBaf4bxJZlI+MnWi43+9a7y8T4c5Fu/aE6Tv9OFvMLOgQkQckuHIJjCviyVWg8Veg/pRxQQEy5jZoPrqq4tRnrew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791233689; c=relaxed/simple; bh=ZDwYvAX4AqSpiCy1YXGCSHB4tjNDhbvCD+TQPrtx30c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YteGXdEACEqJXeTkeaQ3s7IOcGqomhSR8ywDZVPntiLTpjwpMgh0fRvHtBBdXT+qg1rtmQR0qbM5OrRnOpjuBKcutwbrLV1llEkYqAldEGwID9JlSDSYolDCbW9jogEpbAX22gzmUh0HFXLzYqUi1Sgip6a8PXH+T2pAJXY4WD4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ie+XEJvN; 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="Ie+XEJvN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EA5C1F000FF; Mon, 5 Oct 2026 20:54:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791233686; bh=+vwOL9vMIhK+J5RmKBslcQpJUCBdOIyFZM8/IBqsHiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ie+XEJvNmh2Z8SazjZrYrNA7VomwE5KSBtYv9TwZP9/eFXJz3ajaXnKolbsWxIfyd +cwZry118ln6DvL1yBso+mvCsmDTLn7e5faGI0fbLvN0OKawIDFHMKvto4p3r3T+g2 jYT6Ae2r09WiE5ybORrOhkSb9wzB4FGEN/OhHO7/1juX6c/T6V0Vir5eLv+JEpD0n5 1DuHslp0eXMmMmtXtJKfXJs9/8tLZM0HO8ZQhpz8TgysTcM9JHECUgAcNzljjPTbOI oxm8KLdYlAKurYYM8y8TXN8X9d2NPZ7Zl5uAPWsTXNrzo09Lwe0kWN6dFYKN1tOZ4l xIKq9l4St7GjA== From: Sasha Levin To: stable@vger.kernel.org Cc: Johan Hovold , stable , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.1.y] tty: tty_port: restore TTY_IO_ERROR on activation failure Date: Mon, 5 Oct 2026 16:54:42 -0400 Message-ID: <20261005205257.3275534-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100522-tidings-ouch-9669@gregkh> References: <2026100522-tidings-ouch-9669@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 the existing braced error block with explicit mutex_unlock(). ] 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 494500c453ccb..6f3b4eeb44b38 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -783,6 +783,7 @@ 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