Hello, While fuzzing, I found an input that triggers an assertion failure through virtio-rng -> vring_split_desc_read. Maybe this is related to: Message-ID: <20200511033001.dzvtbdhl3oz5p...@mozz.bu.edu> Assertion failure through virtio_lduw_phys_cached
#8 0x7fe6a9acf091 in __assert_fail /build/glibc-GwnBeO/glibc-2.30/assert/assert.c:101:3 #9 0x564cbe7d96fd in address_space_read_cached include/exec/memory.h:2423:5 #10 0x564cbe7e79c5 in vring_split_desc_read hw/virtio/virtio.c:236:5 #11 0x564cbe7e84ce in virtqueue_split_read_next_desc hw/virtio/virtio.c:929:5 #12 0x564cbe78f86b in virtqueue_split_get_avail_bytes hw/virtio/virtio.c:1009:18 #13 0x564cbe78ab22 in virtqueue_get_avail_bytes hw/virtio/virtio.c:1208:9 #14 0x564cc08aade1 in get_request_size hw/virtio/virtio-rng.c:40:5 #15 0x564cc08aa20b in virtio_rng_process hw/virtio/virtio-rng.c:115:12 #16 0x564cc08a8c48 in virtio_rng_set_status hw/virtio/virtio-rng.c:172:5 #17 0x564cbe7a50be in virtio_set_status hw/virtio/virtio.c:1876:9 #18 0x564cc08d1b8f in virtio_pci_common_write hw/virtio/virtio-pci.c:1245:9 I can reproduce it in a qemu 5.0 build using these qtest commands: https://paste.debian.net/plain/1146089 (not including them here, as some are quite long) wget https://paste.debian.net/plain/1146089 -O qtest-trace; ~/Development/qemu/build/i386-softmmu/qemu-system-i386 -M pc-q35-5.0 -device virtio-rng-pci,addr=04.0 -display none -nodefaults -nographic -qtest stdio < qtest-trace Please let me know if I can provide any further info. -Alex
