diff mbox series

[v2,1/4] mmc: core: Add check for NULL pointer access

Message ID a4f22132015159005c41f7cce0b361b363c7b845.1583470026.git.nguyenb@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series SD card bug fixes | expand

Commit Message

Bao D. Nguyen March 6, 2020, 4:58 a.m. UTC 
If the SD card is removed, the mmc_card pointer can be set to NULL
by the mmc_sd_remove() function. Check mmc_card pointer to avoid NULL
pointer access.

Signed-off-by: Bao D. Nguyen <nguyenb@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
 drivers/mmc/core/core.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Ulf Hansson March 6, 2020, 10:34 a.m. UTC | #1 
On Fri, 6 Mar 2020 at 05:59, Bao D. Nguyen <nguyenb@codeaurora.org> wrote:
>
> If the SD card is removed, the mmc_card pointer can be set to NULL
> by the mmc_sd_remove() function. Check mmc_card pointer to avoid NULL
> pointer access.

As stated in the other replies, this is just a vague explanation to a
*potential* problem.

Please explain the details for how this problem can occur - or a way
to reproduce the problem.

Kind regards
Uffe

>
> Signed-off-by: Bao D. Nguyen <nguyenb@codeaurora.org>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---
>  drivers/mmc/core/core.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 6b38c19..94441a0 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -666,6 +666,9 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
>  {
>         unsigned int mult;
>
> +       if (!card)
> +               return;
> +
>         /*
>          * SDIO cards only define an upper 1 s limit on access.
>          */
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
diff mbox series

Patch

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6b38c19..94441a0 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -666,6 +666,9 @@  void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
 {
 	unsigned int mult;
 
+	if (!card)
+		return;
+
 	/*
 	 * SDIO cards only define an upper 1 s limit on access.
 	 */