[PATCH] mmc: via-sdmmc: fix return value check of mmc_add_host()

[PATCH] mmc: via-sdmmc: fix return value check of mmc_add_host()

[Yang Yingliang]

mmc_add_host() may return error, if we ignore its return value,
it will lead two issues:
1. The memory that allocated in mmc_alloc_host() is leaked.
2. In the remove() path, mmc_remove_host() will be called to
   delete device, but it's not added yet, it will lead a kernel
   crash because of null-ptr-deref in device_del().

Fix this by checking the return value and goto error path which
will call mmc_free_host().

Fixes: f0bf7f61b840 ("mmc: Add new via-sdmmc host controller driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/mmc/host/via-sdmmc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
index 88662a90ed96..a2b0d9461665 100644
--- a/drivers/mmc/host/via-sdmmc.c
+++ b/drivers/mmc/host/via-sdmmc.c
@@ -1151,7 +1151,9 @@ static int via_sd_probe(struct pci_dev *pcidev,
 	    pcidev->subsystem_device == 0x3891)
 		sdhost->quirks = VIA_CRDR_QUIRK_300MS_PWRDELAY;
 
-	mmc_add_host(mmc);
+	ret = mmc_add_host(mmc);
+	if (ret)
+		goto unmap;
 
 	return 0;
 
-- 
2.25.1

Re: [PATCH] mmc: via-sdmmc: fix return value check of mmc_add_host()

[Ulf Hansson]

On Tue, 8 Nov 2022 at 14:11, Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> mmc_add_host() may return error, if we ignore its return value,
> it will lead two issues:
> 1. The memory that allocated in mmc_alloc_host() is leaked.
> 2. In the remove() path, mmc_remove_host() will be called to
>    delete device, but it's not added yet, it will lead a kernel
>    crash because of null-ptr-deref in device_del().
>
> Fix this by checking the return value and goto error path which
> will call mmc_free_host().
>
> Fixes: f0bf7f61b840 ("mmc: Add new via-sdmmc host controller driver")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/via-sdmmc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
> index 88662a90ed96..a2b0d9461665 100644
> --- a/drivers/mmc/host/via-sdmmc.c
> +++ b/drivers/mmc/host/via-sdmmc.c
> @@ -1151,7 +1151,9 @@ static int via_sd_probe(struct pci_dev *pcidev,
>             pcidev->subsystem_device == 0x3891)
>                 sdhost->quirks = VIA_CRDR_QUIRK_300MS_PWRDELAY;
>
> -       mmc_add_host(mmc);
> +       ret = mmc_add_host(mmc);
> +       if (ret)
> +               goto unmap;
>
>         return 0;
>
> --
> 2.25.1
>