Fuzzing the Linux kernel with syzkaller allowed to find how to crash qemu using a special SCSI_IOCTL_SEND_COMMAND. It hits the assertion in ide_dma_cb() introduced in the commit a718978ed58a in July 2015. Currently this bug is not reproduced by the unit tests.
Let's improve the ide-test to cover more PRDT cases including one that causes this particular qemu crash. The test is developed according to the Programming Interface for Bus Master IDE Controller (Revision 1.0 5/16/94). Signed-off-by: Alexander Popov <[email protected]> --- tests/ide-test.c | 137 +++++++++++++++++++++-------------------------- 1 file changed, 61 insertions(+), 76 deletions(-) diff --git a/tests/ide-test.c b/tests/ide-test.c index 0277e7d5a9..f042d8a700 100644 --- a/tests/ide-test.c +++ b/tests/ide-test.c @@ -445,7 +445,8 @@ static void test_bmdma_trim(void) test_bmdma_teardown(qts); } -static void test_bmdma_short_prdt(void) +static void test_bmdma_prdt(uint32_t prdt_size, int nb_sectors, + uint8_t req_status, uint8_t abort_req_status) { QTestState *qts; QPCIDevice *dev; @@ -455,94 +456,81 @@ static void test_bmdma_short_prdt(void) PrdtEntry prdt[] = { { .addr = 0, - .size = cpu_to_le32(0x10 | PRDT_EOT), + .size = cpu_to_le32(prdt_size | PRDT_EOT), }, }; qts = test_bmdma_setup(); - dev = get_pci_device(qts, &bmdma_bar, &ide_bar); - /* Normal request */ - status = send_dma_request(qts, CMD_READ_DMA, 0, 1, + /* Test the request */ + status = send_dma_request(qts, CMD_READ_DMA, 0, nb_sectors, prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, 0); + g_assert_cmphex(status, ==, req_status); assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); - /* Abort the request before it completes */ - status = send_dma_request(qts, CMD_READ_DMA | CMDF_ABORT, 0, 1, - prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, 0); + /* Now test aborting the same request */ + status = send_dma_request(qts, CMD_READ_DMA | CMDF_ABORT, 0, + nb_sectors, prdt, ARRAY_SIZE(prdt), NULL); + g_assert_cmphex(status, ==, abort_req_status); assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); - free_pci_device(dev); - test_bmdma_teardown(qts); -} -static void test_bmdma_one_sector_short_prdt(void) -{ - QTestState *qts; - QPCIDevice *dev; - QPCIBar bmdma_bar, ide_bar; - uint8_t status; - - /* Read 2 sectors but only give 1 sector in PRDT */ - PrdtEntry prdt[] = { - { - .addr = 0, - .size = cpu_to_le32(0x200 | PRDT_EOT), - }, - }; - - qts = test_bmdma_setup(); - - dev = get_pci_device(qts, &bmdma_bar, &ide_bar); - - /* Normal request */ - status = send_dma_request(qts, CMD_READ_DMA, 0, 2, - prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, 0); - assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); - - /* Abort the request before it completes */ - status = send_dma_request(qts, CMD_READ_DMA | CMDF_ABORT, 0, 2, - prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, 0); - assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); free_pci_device(dev); test_bmdma_teardown(qts); } -static void test_bmdma_long_prdt(void) +/* + * This test is developed according to the Programming Interface for + * Bus Master IDE Controller (Revision 1.0 5/16/94) + */ +static void test_bmdma_various_prdts(void) { - QTestState *qts; - QPCIDevice *dev; - QPCIBar bmdma_bar, ide_bar; - uint8_t status; - - PrdtEntry prdt[] = { - { - .addr = 0, - .size = cpu_to_le32(0x1000 | PRDT_EOT), - }, - }; - - qts = test_bmdma_setup(); - - dev = get_pci_device(qts, &bmdma_bar, &ide_bar); - - /* Normal request */ - status = send_dma_request(qts, CMD_READ_DMA, 0, 1, - prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, BM_STS_ACTIVE | BM_STS_INTR); - assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); + uint32_t size = 0; + uint32_t prd_size = 0; + int req_sectors = 0; + uint32_t req_size = 0; + uint8_t s1 = 0, s2 = 0; + + for (size = 0; size < 65536; size += 256) { + /* + * Two bytes specify the count of the region in bytes. + * The bit 0 is always set to 0. + * A value of zero in these two bytes indicates 64K. + */ + prd_size = size & 0xfffe; + if (prd_size == 0) { + prd_size = 65536; + } - /* Abort the request before it completes */ - status = send_dma_request(qts, CMD_READ_DMA | CMDF_ABORT, 0, 1, - prdt, ARRAY_SIZE(prdt), NULL); - g_assert_cmphex(status, ==, BM_STS_INTR); - assert_bit_clear(qpci_io_readb(dev, ide_bar, reg_status), DF | ERR); - free_pci_device(dev); - test_bmdma_teardown(qts); + for (req_sectors = 1; req_sectors <= 256; req_sectors *= 2) { + req_size = req_sectors * 512; + + /* + * 1. If PRDs specified a smaller size than the IDE transfer + * size, then the Interrupt and Active bits in the Controller + * status register are not set (Error Condition). + * + * 2. If the size of the physical memory regions was equal to + * the IDE device transfer size, the Interrupt bit in the + * Controller status register is set to 1, Active bit is set to 0. + * + * 3. If PRDs specified a larger size than the IDE transfer size, + * the Interrupt and Active bits in the Controller status register + * are both set to 1. + */ + if (prd_size < req_size) { + s1 = 0; + s2 = 0; + } else if (prd_size == req_size) { + s1 = BM_STS_INTR; + s2 = BM_STS_INTR; + } else { + s1 = BM_STS_ACTIVE | BM_STS_INTR; + s2 = BM_STS_INTR; + } + test_bmdma_prdt(size, req_sectors, s1, s2); + } + } } static void test_bmdma_no_busmaster(void) @@ -1066,10 +1054,7 @@ int main(int argc, char **argv) qtest_add_func("/ide/bmdma/simple_rw", test_bmdma_simple_rw); qtest_add_func("/ide/bmdma/trim", test_bmdma_trim); - qtest_add_func("/ide/bmdma/short_prdt", test_bmdma_short_prdt); - qtest_add_func("/ide/bmdma/one_sector_short_prdt", - test_bmdma_one_sector_short_prdt); - qtest_add_func("/ide/bmdma/long_prdt", test_bmdma_long_prdt); + qtest_add_func("/ide/bmdma/various_prdts", test_bmdma_various_prdts); qtest_add_func("/ide/bmdma/no_busmaster", test_bmdma_no_busmaster); qtest_add_func("/ide/flush", test_flush); -- 2.23.0
