The VM crashes if the root directory doesn't exist

[wainersm]

If I configure krun with an invalid root directory (krun_set_root()) and start the VM then it will simply crash. Shouldn't rather it fails nicely?

It can be reproduced with the chroot_vm program:

$ ./chroot_vm rootfs_not_exist_dir /bin/sh
[    0.038923] Kernel panic - not syncing: Requested init /init.krun failed (error -2).
[    0.039014] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.10 #1
[    0.039044] Call Trace:
[    0.039062]  show_stack+0x3d/0x3f
[    0.039124]  dump_stack+0x5e/0x74
[    0.039140]  ? rest_init+0xa0/0xa5
[    0.039159]  panic+0xf6/0x2a4
[    0.039178]  ? kernel_execve+0x145/0x1b0
[    0.039198]  ? rest_init+0xa5/0xa5
[    0.039220]  kernel_init+0xa5/0xfb
[    0.039238]  ret_from_fork+0x1f/0x30
[    0.039273] Kernel Offset: disabled

[slp]

It's the caller, chroot_vm in this case, the one that's responsible to check that the directory specified as root filesystem is available by the time krun_start_enter() is called. This also applies to the directories configured as mapped volumes.

I'll update the chroot_vm.c example to do those checks. Thanks for pointing this out.

[wainersm]

@slp ok, got it. What kind of errors will krun_start_enter() return -1?

[slp]

@wainersm krun_start_enter(ctx) will return < 0 if ctx is not a valid context or has not been properly configured, or there has been an internal error setting up EventManager or the VMM.