[PATCH 3.12 19/82] spi: Fix crash with double message finalisation on error handling

Greg Kroah-Hartman
2014-02-20T23:51:59Z

From: Geert Uytterhoeven <geert+renesas@linux-m68k.org>

commit 1f802f8249a0da536877842c43c7204064c4de8b upstream.

This reverts commit e120cc0dcf2880a4c5c0a6cb27b655600a1cfa1d.

It causes a NULL pointer dereference with drivers using the generic
spi_transfer_one_message(), which always calls
spi_finalize_current_message(), which zeroes master->cur_msg.

Drivers implementing transfer_one_message() theirselves must always call
spi_finalize_current_message(), even if the transfer failed:

* @transfer_one_message: the subsystem calls the driver to transfer a single
* message while queuing transfers that arrive in the meantime. When the
* driver is finished with this message, it must call
* spi_finalize_current_message() so the subsystem can issue the next
* transfer

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/spi/spi.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -600,9 +600,7 @@ static void spi_pump_messages(struct kth
ret = master->transfer_one_message(master, master->cur_msg);
if (ret) {
dev_err(&master->dev,
- "failed to transfer one message from queue: %d\n", ret);
- master->cur_msg->status = ret;
- spi_finalize_current_message(master);
+ "failed to transfer one message from queue\n");
return;
}
}