[PATCH v2] i2c: i2c-mt65xx: fix NULL ptr dereference

[PATCH v2] i2c: i2c-mt65xx: fix NULL ptr dereference

[Fabien Parent]

Since commit abf4923e97c3 ("i2c: mediatek: disable zero-length transfers
for mt8183"), there is a NULL pointer dereference for all the SoCs
that don't have any quirk. mtk_i2c_functionality is not checking that
the quirks pointer is not NULL before starting to use it.

This commit add a call to i2c_check_quirks which will check whether
the quirks pointer is set, and if so will check if the IP has the
NO_ZERO_LEN quirk.

Fixes: abf4923e97c3 ("i2c: mediatek: disable zero-length transfers for mt8183")
Signed-off-by: Fabien Parent <fparent@baylibre.com>
---

v2:
	* use i2c_check_quirks to check the quirks

---
 drivers/i2c/busses/i2c-mt65xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 29eae1bf4f86..2152ec5f535c 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -875,7 +875,7 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 
 static u32 mtk_i2c_functionality(struct i2c_adapter *adap)
 {
-	if (adap->quirks->flags & I2C_AQ_NO_ZERO_LEN)
+	if (i2c_check_quirks(adap, I2C_AQ_NO_ZERO_LEN))
 		return I2C_FUNC_I2C |
 			(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 	else
-- 
2.23.0

Re: [PATCH v2] i2c: i2c-mt65xx: fix NULL ptr dereference

[Cengiz Can]

On 2019-09-30 18:28, Fabien Parent wrote:
> Fixes: abf4923e97c3 ("i2c: mediatek: disable zero-length transfers for 
> mt8183")
> Signed-off-by: Fabien Parent <fparent@baylibre.com>

Reviewed-by: Cengiz Can <cengiz@kernel.wtf>

Re: [PATCH v2] i2c: i2c-mt65xx: fix NULL ptr dereference

[Hsin-Yi Wang]

On Mon, Sep 30, 2019 at 2:20 PM Cengiz Can <cengiz@kernel.wtf> wrote:
>
> On 2019-09-30 18:28, Fabien Parent wrote:
> > Fixes: abf4923e97c3 ("i2c: mediatek: disable zero-length transfers for
> > mt8183")
> > Signed-off-by: Fabien Parent <fparent@baylibre.com>
>
> Reviewed-by: Cengiz Can <cengiz@kernel.wtf>
Reviewed-by: Hsin-Yi Wang <hsinyi@chromium.org>

Thanks!

Re: [PATCH v2] i2c: i2c-mt65xx: fix NULL ptr dereference

[Ulrich Hecht]

> On September 30, 2019 at 5:28 PM Fabien Parent <fparent@baylibre.com> wrote:
> 
> 
> Since commit abf4923e97c3 ("i2c: mediatek: disable zero-length transfers
> for mt8183"), there is a NULL pointer dereference for all the SoCs
> that don't have any quirk. mtk_i2c_functionality is not checking that
> the quirks pointer is not NULL before starting to use it.
> 
> This commit add a call to i2c_check_quirks which will check whether
> the quirks pointer is set, and if so will check if the IP has the
> NO_ZERO_LEN quirk.
> 
> Fixes: abf4923e97c3 ("i2c: mediatek: disable zero-length transfers for mt8183")
> Signed-off-by: Fabien Parent <fparent@baylibre.com>

Thank you! Tested successfully on Acer R13 Chromebook (mt8173).

Tested-by: Ulrich Hecht <uli@fpond.eu>

CU
Uli