Hi, I'm trying to write a virtio-blk driver for Solaris. I've gotten it to the point where Solaris can see the device and create a ZFS file system on it. However when I try and create a UFS filesystem on the device, the VM crashed with the error *** glibc detected *** /usr/bin/qemu-kvm: double free or corruption (!prev): 0x00007f2d38000a00 *** I can reproduce the problem with a simple dd, i.e. dd if=/dev/zero of=/dev/rdsk/c2d10p0 bs=5000 count=1 My driver will create a virtio-blk request with two elements in the sg list, one for the first 4096 byes and the other for the remaining 904. >From stepping through with gdb, virtio_blk_handle_write will sets n_sectors to 9 (5000 / 512). Later on the code, n_sectors is used the calculate the size of the buffer required but 9 * 512 is too small and so when the request is process it ends up writing past the end of the buffer and I guest this triggers the glibc error. Is there a requirement for virtio-blk guest drivers that all i/o requests are sized in multiples of 512 bytes? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
