spi: trigger trace event for message-done before mesg->complete

Uwe Kleine-König · broonie · commit 391949b6f021 · 2015-03-18T11:34:10.000Z
With spidev the mesg-&gt;complete callback points to spidev_complete.
Calling this unblocks spidev_sync and so spidev_sync_write finishes. As
the struct spi_message just read is a local variable in
spidev_sync_write and recording the trace event accesses this message
the recording is better done first. The same can happen for
spidev_sync_read.

This fixes an oops observed on a 3.14-rt system with spidev activity
after

	echo 1 &gt; /sys/kernel/debug/tracing/events/spi/enable

.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Cc: stable@vger.kernel.org
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
@@ -1105,13 +1105,14 @@ void spi_finalize_current_message(struct spi_master *master)
 				"failed to unprepare message: %d\n", ret);
 		}
 	}
+
+	trace_spi_message_done(mesg);
+
 	master->cur_msg_prepared = false;
 
 	mesg->state = NULL;
 	if (mesg->complete)
 		mesg->complete(mesg->context);
-
-	trace_spi_message_done(mesg);
 }
 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
 

Original file line number	Diff line number	Diff line change
`@@ -1105,13 +1105,14 @@ void spi_finalize_current_message(struct spi_master *master)`
`1105`	`1105`	`"failed to unprepare message: %d\n", ret);`
`1106`	`1106`	`}`
`1107`	`1107`	`}`
	`1108`	`+`
	`1109`	`+ trace_spi_message_done(mesg);`
	`1110`	`+`
`1108`	`1111`	`master->cur_msg_prepared = false;`
`1109`	`1112`
`1110`	`1113`	`mesg->state = NULL;`
`1111`	`1114`	`if (mesg->complete)`
`1112`	`1115`	`mesg->complete(mesg->context);`
`1113`		`-`
`1114`		`- trace_spi_message_done(mesg);`
`1115`	`1116`	`}`
`1116`	`1117`	`EXPORT_SYMBOL_GPL(spi_finalize_current_message);`
`1117`	`1118`