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serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES

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Aliases >= MAX_UART_INSTANCES is no problem to find out and use but in
error path is necessary skip clearing bits in bitmap to ensure that only
bits in allocated bitmap are handled and nothing beyond that.
Without this patch when for example serial90 alias is used then in error
patch bit 90 is clear in 32bit wide bitmap.

Fixes: ae1cca3fa3 ("serial: uartps: Change uart ID port allocation")
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michal Simek 2018-10-08 14:17:19 +02:00 committed by Greg Kroah-Hartman
parent 33a1a7be19
commit 2088cfd882
1 changed files with 4 additions and 2 deletions
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6
drivers/tty/serial/xilinx_uartps.c
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@ -1668,7 +1668,8 @@ err_out_unregister_driver:
uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
err_out_id:
mutex_lock(&bitmap_lock);
clear_bit(cdns_uart_data->id, bitmap);
if (cdns_uart_data->id < MAX_UART_INSTANCES)
clear_bit(cdns_uart_data->id, bitmap);
mutex_unlock(&bitmap_lock);
return rc;
}
@ -1693,7 +1694,8 @@ static int cdns_uart_remove(struct platform_device *pdev)
rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
port->mapbase = 0;
mutex_lock(&bitmap_lock);
clear_bit(cdns_uart_data->id, bitmap);
if (cdns_uart_data->id < MAX_UART_INSTANCES)
clear_bit(cdns_uart_data->id, bitmap);
mutex_unlock(&bitmap_lock);
clk_disable_unprepare(cdns_uart_data->uartclk);
clk_disable_unprepare(cdns_uart_data->pclk);