On Wed, Jul 25, 2012 at 10:44:14AM +0200, Paolo Bonzini wrote: > Il 25/07/2012 10:29, Wang Sen ha scritto: > > When using the commands below to write some data to a virtio-scsi LUN of the > > QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash. > > > > # sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.) > > # sudo mount /dev/sdb /mnt > > # dd if=/dev/zero of=/mnt/file bs=1M count=1024 > > > > In current implementation, sg_set_buf is called to add buffers to sg list which > > is put into the virtqueue eventually. But there are some HighMem pages in > > table->sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may > > return NULL value. This will cause QEMU exit when virtqueue_map_sg is called > > in QEMU because an invalid GPA is passed by virtqueue. > > Heh, I was compiling (almost) the same patch as we speak. :) > > I've never seen QEMU crash; the VM would more likely just fail to boot > with a panic. But it's the same bug anyway. It's not a segfault "crash", I think it hits an abort(3) in QEMU's virtio code when trying to map an invalid guest physical address. Stefan -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
