[PATCH v2] spi: uniphier: Fix completion initialization order before devm_request_irq()

[Kunihiko Hayashi <hayashi.kunihiko@socionext.com>]

The driver calls devm_request_irq() before initializing the completion
used by the interrupt handler. Because the interrupt may occur immediately
after devm_request_irq(), the handler may execute before init_completion().

This may result in calling complete() on an uninitialized completion,
causing undefined behavior. This has been observed with KASAN.

Fix this by initializing the completion before registering the IRQ.

Reported-by: Sangyun Kim <sangyun.kim@snu.ac.kr>
Reported-by: Kyungwook Boo <bookyungwook@gmail.com>
Fixes: 5ba155a4d4cc ("spi: add SPI controller driver for UniPhier SoC")
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
---
Changes in v2:
- Rebase onto latest, no functional changes

drivers/spi/spi-uniphier.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-uniphier.c b/drivers/spi/spi-uniphier.c
index cc20fd11f03f..86fce9a571da 100644
--- a/drivers/spi/spi-uniphier.c
+++ b/drivers/spi/spi-uniphier.c
@@ -656,6 +656,8 @@ static int uniphier_spi_probe(struct platform_device *pdev)
 	priv->host = host;
 	priv->is_save_param = false;
 
+	init_completion(&priv->xfer_done);
+
 	priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
@@ -679,8 +681,6 @@ static int uniphier_spi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	init_completion(&priv->xfer_done);
-
 	clk_rate = clk_get_rate(priv->clk);
 
 	host->max_speed_hz = DIV_ROUND_UP(clk_rate, SSI_MIN_CLK_DIVIDER);
-- 
2.34.1