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Commit d8434c31 authored by John Sperbeck's avatar John Sperbeck Committed by Wolfram Sang
Browse files

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: default avatarJohn Sperbeck <jsperbeck@google.com>
Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 237b5f66

drivers/i2c/i2c-core-smbus.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

include/trace/events/smbus.h

+3 −3
Original line number Diff line number Diff line
@@ -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			)