On Tue, 12 Feb 2019 19:40:57 -0800 John Sperbeck <jsperbeck@xxxxxxxxxx> wrote: > If an smbus transfer fails, there's no guarantee that the output > buffer was written. So, avoid trying to show the output buffer when > tracing after an error. This was 'mostly harmless', but would trip > up kasan checking if left-over cruft in byte 0 is a large length, > causing us to read from unwritten memory. >From a tracing viewpoint: Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> -- Steve > > Signed-off-by: John Sperbeck <jsperbeck@xxxxxxxxxx> > --- > drivers/i2c/i2c-core-smbus.c | 2 +- > include/trace/events/smbus.h | 6 +++--- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index 9cd66cabb84f..132119112596 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -585,7 +585,7 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, > trace: > /* If enabled, the reply tracepoint is conditional on read_write. */ > trace_smbus_reply(adapter, addr, flags, read_write, > - command, protocol, data); > + command, protocol, data, res); > trace_smbus_result(adapter, addr, flags, read_write, > command, protocol, res); > > diff --git a/include/trace/events/smbus.h b/include/trace/events/smbus.h > index d2fb6e1d3e10..a4892a187842 100644 > --- a/include/trace/events/smbus.h > +++ b/include/trace/events/smbus.h > @@ -138,9 +138,9 @@ TRACE_EVENT_CONDITION(smbus_reply, > TP_PROTO(const struct i2c_adapter *adap, > u16 addr, unsigned short flags, > char read_write, u8 command, int protocol, > - const union i2c_smbus_data *data), > - TP_ARGS(adap, addr, flags, read_write, command, protocol, data), > - TP_CONDITION(read_write == I2C_SMBUS_READ), > + const union i2c_smbus_data *data, int res), > + TP_ARGS(adap, addr, flags, read_write, command, protocol, data, res), > + TP_CONDITION(res >= 0 && read_write == I2C_SMBUS_READ), > TP_STRUCT__entry( > __field(int, adapter_nr ) > __field(__u16, addr )
