1# Troubleshooting
2
3Here are some things to check if there are problems running syzkaller.
4
5 - Check that QEMU can successfully boot the virtual machine.  For example,
6   if `IMAGE` is set to the VM's disk image (as per the `image` config value)
7   and `KERNEL` is set to the test kernel (as per the `kernel` config value)
8   then something like the following command should start the VM successfully:
9
10     ```shell
11     qemu-system-x86_64 -hda $IMAGE -m 256 -net nic -net user,host=10.0.2.10,hostfwd=tcp::23505-:22 -enable-kvm -kernel $KERNEL -append root=/dev/sda
12     ```
13
14 - Check that inbound SSH to the running virtual machine works.  For example, with
15   a VM running and with `SSHKEY` set to the SSH identity (as per the `sshkey` config value) the
16   following command should connect:
17
18     ```shell
19     ssh -i $SSHKEY -p 23505 root@localhost
20     ```
21
22 - If you *are* having SSH difficulties, make sure your kernel configuration
23   has networking enabled. Sometimes defconfig errs minimalistic and omits the
24   following necessary options:
25     ```shell
26     CONFIG_VIRTIO_NET=y
27     CONFIG_E1000=y
28     CONFIG_E1000E=y
29     ```
30
31 - Check that the `CONFIG_KCOV` option is available inside the VM:
32    - `ls /sys/kernel/debug       # Check debugfs mounted`
33    - `ls /sys/kernel/debug/kcov  # Check kcov enabled`
34    - Build the test program from `Documentation/kcov.txt` and run it inside the VM.
35
36 - Check that debug information (from the `CONFIG_DEBUG_INFO` option) is available
37    - Pass the hex output from the kcov test program to `addr2line -a -i -f -e $VMLINUX` (where
38      `VMLINUX` is the vmlinux file, as per the `kernel_obj` config value), to confirm
39      that symbols for the kernel are available.
40
41Also see [this](/docs/troubleshooting.md) for generic troubleshooting advice.
42
43If none of the above helps, file a bug on [the bug tracker](https://github.com/google/syzkaller/issues)
44or ask us directly on the syzkaller@googlegroups.com mailing list.
45Please include syzkaller commit id that you use and `syz-manager` output with `-debug` flag enabled if applicable.
46