On 04/09/2019 10.22, Austin Kim wrote:
> If the kmalloc() return NULL, the NULL pointer dereference will occur.
> new_ts->ts = ts;
>
> Add exception check after the call to kmalloc() is made.
>
> Signed-off-by: Austin Kim <austindh....@gmail.com>
> ---
> drivers/staging/media/meson/vdec/vdec_helpers.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.c
> b/drivers/staging/media/meson/vdec/vdec_helpers.c
> index f16948b..e7e56d5 100644
> --- a/drivers/staging/media/meson/vdec/vdec_helpers.c
> +++ b/drivers/staging/media/meson/vdec/vdec_helpers.c
> @@ -206,6 +206,10 @@ void amvdec_add_ts_reorder(struct amvdec_session *sess,
> u64 ts, u32 offset)
> unsigned long flags;
>
> new_ts = kmalloc(sizeof(*new_ts), GFP_KERNEL);
> + if (!new_ts) {
> + dev_err(sess->core->dev, "Failed to kmalloc()\n");
> + return;
> + }
> new_ts->ts = ts;
> new_ts->offset = offset;
No need to printk() on error, AFAIK the mm subsystem should already make
some noise if an allocation fails.
This is not a proper fix - you need to make the function return an error
(-ENOMEM) to let the caller know allocation failed, and allow that to
propagate the error. There's only one caller, which already seems
capable of returning errors (there's an -EAGAIN), so it shouldn't be
that hard - though of course one needs to undo what has been done so far.
Also, unrelated to the kmalloc() handling: amvdec_add_ts_reorder() could
be moved to esparser.c and made static, or at the very least the
EXPORT_SYMBOL can be removed since vdec_helpers.o is linked in to the
same module as the sole user. That probably goes for all the
EXPORT_SYMBOL(amvdec_*).
Rasmus
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