On Tue, 11 Jan 2022 at 07:52, Heyi Guo <guoheyi@xxxxxxxxxxxxxxxxx> wrote: > > Hi all, > > Any comments? > > Thanks, > > Heyi > > 在 2022/1/9 下午9:26, Heyi Guo 写道: > > The memory will be freed by the caller if transfer timeout occurs, > > then it would trigger kernel panic if the peer device responds with > > something after timeout and triggers the interrupt handler of aspeed > > i2c driver. > > > > Set the msgs pointer to NULL to avoid invalid memory reference after > > timeout to fix this potential kernel panic. Thanks for the patch. How did you discover this issue? Do you have a test I can run to reproduce the crash? Can you provide a Fixes tag? Do other i2c master drivers do this? I took a quick look at the meson driver and it doesn't appear to clear it's pointer to msgs. > > > > Signed-off-by: Heyi Guo <guoheyi@xxxxxxxxxxxxxxxxx> > > > > ------- > > > > Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx> > > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > > Cc: Joel Stanley <joel@xxxxxxxxx> > > Cc: Andrew Jeffery <andrew@xxxxxxxx> > > Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > Cc: linux-i2c@xxxxxxxxxxxxxxx > > Cc: openbmc@xxxxxxxxxxxxxxxx > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > Cc: linux-aspeed@xxxxxxxxxxxxxxxx > > --- > > drivers/i2c/busses/i2c-aspeed.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c > > index 67e8b97c0c950..3ab0396168680 100644 > > --- a/drivers/i2c/busses/i2c-aspeed.c > > +++ b/drivers/i2c/busses/i2c-aspeed.c > > @@ -708,6 +708,11 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap, > > spin_lock_irqsave(&bus->lock, flags); > > if (bus->master_state == ASPEED_I2C_MASTER_PENDING) > > bus->master_state = ASPEED_I2C_MASTER_INACTIVE; > > + /* > > + * All the buffers may be freed after returning to caller, so > > + * set msgs to NULL to avoid memory reference after freeing. > > + */ > > + bus->msgs = NULL; > > spin_unlock_irqrestore(&bus->lock, flags); > > > > return -ETIMEDOUT;
