Re: [Qemu-devel] [PATCH v5 07/17] sdhci: refactor common sysbus/pci unrealize() into sdhci_common_unrealize()

[Alistair Francis]

On Wed, Jan 3, 2018 at 10:07 AM, Philippe Mathieu-Daudé <address@hidden> wrote:
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
>  hw/sd/sdhci.c | 25 ++++++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
> index b3dbd994fd..089961bd66 100644
> --- a/hw/sd/sdhci.c
> +++ b/hw/sd/sdhci.c
> @@ -31,6 +31,7 @@
>  #include "qemu/bitops.h"
>  #include "hw/sd/sdhci.h"
>  #include "sdhci-internal.h"
> +#include "qapi/error.h"
>  #include "qemu/log.h"
>
>  /* host controller debug messages */
> @@ -1203,15 +1204,23 @@ static void sdhci_common_realize(SDHCIState *s, Error 
> **errp)
>                            SDHC_REGISTERS_MAP_SIZE);
>  }
>
> +static void sdhci_common_unrealize(SDHCIState *s, Error **errp)
> +{
> +    /* This function is expected to be called only once for each class:
> +     * - SysBus:    via DeviceClass->unrealize(),
> +     * - PCI:       via PCIDeviceClass->exit().
> +     * However to avoid double-free and/or use-after-free we still nullify
> +     * this variable (better safe than sorry!). */
> +    g_free(s->fifo_buffer);
> +    s->fifo_buffer = NULL;

Can we assert() on s->fifo_buffer? That way if we are double freeing
it can be caught by developers.

Alistair

> +}
> +
>  static void sdhci_uninitfn(SDHCIState *s)
>  {
>      timer_del(s->insert_timer);
>      timer_free(s->insert_timer);
>      timer_del(s->transfer_timer);
>      timer_free(s->transfer_timer);
> -
> -    g_free(s->fifo_buffer);
> -    s->fifo_buffer = NULL;
>  }
>
>  static bool sdhci_pending_insert_vmstate_needed(void *opaque)
> @@ -1315,6 +1324,8 @@ static void sdhci_pci_realize(PCIDevice *dev, Error 
> **errp)
>  static void sdhci_pci_exit(PCIDevice *dev)
>  {
>      SDHCIState *s = PCI_SDHCI(dev);
> +
> +    sdhci_common_unrealize(s, &error_abort);
>      sdhci_uninitfn(s);
>  }
>
> @@ -1371,11 +1382,19 @@ static void sdhci_sysbus_realize(DeviceState *dev, 
> Error ** errp)
>      sysbus_init_mmio(sbd, &s->iomem);
>  }
>
> +static void sdhci_sysbus_unrealize(DeviceState *dev, Error **errp)
> +{
> +    SDHCIState *s = SYSBUS_SDHCI(dev);
> +
> +    sdhci_common_unrealize(s, &error_abort);
> +}
> +
>  static void sdhci_sysbus_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
>
>      dc->realize = sdhci_sysbus_realize;
> +    dc->unrealize = sdhci_sysbus_unrealize;
>
>      sdhci_common_class_init(klass, data);
>  }
> --
> 2.15.1
>
>