From: Vincent Whitchurch vincent.whitchurch@axis.com
[ Upstream commit 837ba18dfcd4db21ad58107c65bfe89753aa56d7 ]
The "tx/rx-transfer - crossing PAGE_SIZE" test always fails when len=131071 and rx_offset >= 5:
spi-loopback-test spi0.0: Running test tx/rx-transfer - crossing PAGE_SIZE ... with iteration values: len = 131071, tx_off = 0, rx_off = 3 with iteration values: len = 131071, tx_off = 0, rx_off = 4 with iteration values: len = 131071, tx_off = 0, rx_off = 5 loopback strangeness - rx changed outside of allowed range at: ...a4321000 spi_msg@ffffffd5a4157690 frame_length: 131071 actual_length: 131071 spi_transfer@ffffffd5a41576f8 len: 131071 tx_buf: ffffffd5a4340ffc
Note that rx_offset > 3 can only occur if the SPI controller driver sets ->dma_alignment to a higher value than 4, so most SPI controller drivers are not affect.
The allocated Rx buffer is of size SPI_TEST_MAX_SIZE_PLUS, which is 132 KiB (assuming 4 KiB pages). This test uses an initial offset into the rx_buf of PAGE_SIZE - 4, and a len of 131071, so the range expected to be written in this transfer ends at (4096 - 4) + 5 + 131071 == 132 KiB, which is also the end of the allocated buffer. But the code which verifies the content of the buffer reads a byte beyond the allocated buffer and spuriously fails because this out-of-bounds read doesn't return the expected value.
Fix this by using ITERATE_LEN instead of ITERATE_MAX_LEN to avoid testing sizes which cause out-of-bounds reads.
Signed-off-by: Vincent Whitchurch vincent.whitchurch@axis.com Link: https://lore.kernel.org/r/20200902132341.7079-1-vincent.whitchurch@axis.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-loopback-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c index bed7403bb6b3..b9a7117b6dce 100644 --- a/drivers/spi/spi-loopback-test.c +++ b/drivers/spi/spi-loopback-test.c @@ -99,7 +99,7 @@ static struct spi_test spi_tests[] = { { .description = "tx/rx-transfer - crossing PAGE_SIZE", .fill_option = FILL_COUNT_8, - .iterate_len = { ITERATE_MAX_LEN }, + .iterate_len = { ITERATE_LEN }, .iterate_tx_align = ITERATE_ALIGN, .iterate_rx_align = ITERATE_ALIGN, .transfer_count = 1,