spi: fsl-espi: avoid processing uninitalized data on error

arndb · broonie · commit 5c0ba57744b1 · 2016-10-26T11:14:52.000+01:00
When we get a spurious interrupt in fsl_espi_irq, we end up processing four uninitalized bytes of data, as shown in this warning message: drivers/spi/spi-fsl-espi.c: In function 'fsl_espi_irq': drivers/spi/spi-fsl-espi.c:462:4: warning: 'rx_data' may be used uninitialized in this function [-Wmaybe-uninitialized] This adds another check so we skip the data in this case. Fixes: 6319a68 ("spi/fsl-espi: avoid infinite loops on fsl_espi_cpu_irq()") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
@@ -458,7 +458,7 @@ static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
 
 		mspi->len -= rx_nr_bytes;
 
-		if (mspi->rx)
+		if (rx_nr_bytes && mspi->rx)
 			mspi->get_rx(rx_data, mspi);
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -458,7 +458,7 @@ static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)`
`458`	`458`
`459`	`459`	`mspi->len -= rx_nr_bytes;`
`460`	`460`
`461`		`- if (mspi->rx)`
	`461`	`+ if (rx_nr_bytes && mspi->rx)`
`462`	`462`	`mspi->get_rx(rx_data, mspi);`
`463`	`463`	`}`
`464`	`464`