Hi Arnd,
On Thu, 2018-03-15 at 17:19 +0100, Arnd Bergmann wrote:
> gcc-8 reports that we access an array with a negative index
> in an error case:
>
> drivers/gpu/ipu-v3/ipu-prg.c: In function 'ipu_prg_channel_disable':
> drivers/gpu/ipu-v3/ipu-prg.c:252:43: error: array subscript -22 is below array bounds of 'struct ipu_prg_channel[3]' [-Werror=array-bounds]
>
> This moves the range check in front of the first time that
> variable gets used.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
thank you, I've replaced v2 with this version in imx-drm/fixes.
regards
Philipp
> ----
> v1: Originally sent on Dec 4, 2017.
> v2: Sent again on Jan 16, after no reply, Phillipp said it was merged
> v3: Ran into a related problem with CONFIG_UBSAN, sent again fixing both
> ---
> drivers/gpu/ipu-v3/ipu-prg.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/ipu-v3/ipu-prg.c b/drivers/gpu/ipu-v3/ipu-prg.c
> index 97b99500153d..83f9dd934a5d 100644
> --- a/drivers/gpu/ipu-v3/ipu-prg.c
> +++ b/drivers/gpu/ipu-v3/ipu-prg.c
> @@ -250,10 +250,14 @@ void ipu_prg_channel_disable(struct ipuv3_channel *ipu_chan)
> {
> int prg_chan = ipu_prg_ipu_to_prg_chan(ipu_chan->num);
> struct ipu_prg *prg = ipu_chan->ipu->prg_priv;
> - struct ipu_prg_channel *chan = &prg->chan[prg_chan];
> + struct ipu_prg_channel *chan;
> u32 val;
>
> - if (!chan->enabled || prg_chan < 0)
> + if (prg_chan < 0)
> + return;
> +
> + chan = &prg->chan[prg_chan];
> + if (!chan->enabled)
> return;
>
> pm_runtime_get_sync(prg->dev);
> @@ -280,13 +284,15 @@ int ipu_prg_channel_configure(struct ipuv3_channel *ipu_chan,
> {
> int prg_chan = ipu_prg_ipu_to_prg_chan(ipu_chan->num);
> struct ipu_prg *prg = ipu_chan->ipu->prg_priv;
> - struct ipu_prg_channel *chan = &prg->chan[prg_chan];
> + struct ipu_prg_channel *chan;
> u32 val;
> int ret;
>
> if (prg_chan < 0)
> return prg_chan;
>
> + chan = &prg->chan[prg_chan];
> +
> if (chan->enabled) {
> ipu_pre_update(prg->pres[chan->used_pre], *eba);
> return 0;
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