| Message ID | 20190605184045.5ce33d92@wiggum (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spi-bcm2835: Always initialize local variable in bcm2835_wr_fifo_count | expand |
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 9c03da7c18dd..5b0119cc2b07 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -253,12 +253,11 @@ static inline void bcm2835_wr_fifo_count(struct bcm2835_spi *bs, int count) bs->tx_len -= count; while (count > 0) { + val = 0; if (bs->tx_buf) { len = min(count, 4); memcpy(&val, bs->tx_buf, len); bs->tx_buf += len; - } else { - val = 0; } bcm2835_wr(bs, BCM2835_SPI_FIFO, val); count -= 4;
If count is less than 4 and memcpy copies less than 4 bytes into var, some bytes remain uninitialized. These uninitialized bytes are taken from var and written to the BCM2835_SPI_FIFO register. While the hardware probably is able to ignore these extra bytes, it's Undefined Behavior to read uninitialized bytes. So don't do that. Signed-off-by: Michael Buesch <m@bues.ch> Cc: stable@vger.kernel.org --- drivers/spi/spi-bcm2835.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)