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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lukas Wunner <lukas@wunner.de>,
        Peter Ujfalusi <peter.ujfalusi@ti.com>,
        Mark Brown <broonie@kernel.org>
Subject: [PATCH 4.14 221/242] spi: davinci: Fix use-after-free on unbind
Date:   Mon, 28 Dec 2020 13:50:26 +0100
Message-Id: <20201228124915.546348145@linuxfoundation.org>
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From: Lukas Wunner <lukas@wunner.de>

commit 373afef350a93519b4b8d636b0895da8650b714b upstream.

davinci_spi_remove() accesses the driver's private data after it's been
freed with spi_master_put().

Fix by moving the spi_master_put() to the end of the function.

Fixes: fe5fd2540947 ("spi: davinci: Use dma_request_chan() for requesting DMA channel")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: <stable@vger.kernel.org> # v4.7+
Link: https://lore.kernel.org/r/412f7eb1cf8990e0a3a2153f4c577298deab623e.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/spi/spi-davinci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -1085,13 +1085,13 @@ static int davinci_spi_remove(struct pla
 	spi_bitbang_stop(&dspi->bitbang);
 
 	clk_disable_unprepare(dspi->clk);
-	spi_master_put(master);
 
 	if (dspi->dma_rx) {
 		dma_release_channel(dspi->dma_rx);
 		dma_release_channel(dspi->dma_tx);
 	}
 
+	spi_master_put(master);
 	return 0;
 }