Re: [PATCH] hw/char/exynos4210_uart: Fix crash on trying to load VM state

[Guenter Roeck]

On 1/20/22 7:16 AM, Peter Maydell wrote:
> The exynos4210_uart_post_load() function assumes that it is passed
> the Exynos4210UartState, but it has been attached to the
> VMStateDescription for the Exynos4210UartFIFO type.  The result is a
> SIGSEGV when attempting to load VM state for any machine type
> including this device.
>
> Fix the bug by attaching the post-load function to the VMSD for the
> Exynos4210UartState.  This is the logical place for it, because the
> actions it does relate to the entire UART state, not just the FIFO.
>
> Thanks to the bug reporter @TrungNguyen1909 for the clear bug
> description and the suggested fix.
>
> Fixes: c9d3396d80fe7ece9b
>     ("hw/char/exynos4210_uart: Implement post_load function")
> Buglink: https://gitlab.com/qemu-project/qemu/-/issues/638
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   hw/char/exynos4210_uart.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/char/exynos4210_uart.c b/hw/char/exynos4210_uart.c
> index 80d401a3795..addcd59b028 100644
> --- a/hw/char/exynos4210_uart.c
> +++ b/hw/char/exynos4210_uart.c
> @@ -628,7 +628,6 @@ static const VMStateDescription 
> vmstate_exynos4210_uart_fifo = {
>       .name = "exynos4210.uart.fifo",
>       .version_id = 1,
>       .minimum_version_id = 1,
> -    .post_load = exynos4210_uart_post_load,
>       .fields = (VMStateField[]) {
>           VMSTATE_UINT32(sp, Exynos4210UartFIFO),
>           VMSTATE_UINT32(rp, Exynos4210UartFIFO),
> @@ -641,6 +640,7 @@ static const VMStateDescription vmstate_exynos4210_uart = {
>       .name = "exynos4210.uart",
>       .version_id = 1,
>       .minimum_version_id = 1,
> +    .post_load = exynos4210_uart_post_load,
>       .fields = (VMStateField[]) {
>           VMSTATE_STRUCT(rx, Exynos4210UartState, 1,
>                          vmstate_exynos4210_uart_fifo, Exynos4210UartFIFO),