i2c: core-smbus: don't trace smbus_reply data on errors

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.

Signed-off-by: John Sperbeck <jsperbeck@google.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
John Sperbeck 2019-02-12 19:40:57 -08:00 committed by Wolfram Sang
parent 237b5f66e1
commit d8434c3137
2 changed files with 4 additions and 4 deletions

View File

@ -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);

View File

@ -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 )