Re: [Qemu-devel] [PATCH] migrate: Migration aborts abruptly for machine "none"

[Ashijeet Acharya]

On Sun, Jan 29, 2017 at 12:11 AM, Greg Kurz <address@hidden> wrote:
> On Thu, 26 Jan 2017 14:46:52 +0530
> Ashijeet Acharya <address@hidden> wrote:
>
>> Migration of a "none" machine with no RAM crashes abruptly as
>> bitmap_new() fails and thus aborts. Instead, place a check for
>> last_ram_offset() being '0' at the start of ram_save_setup() and
>> error out with a meaningful error message.
>>
>> Signed-off-by: Ashijeet Acharya <address@hidden>
>> ---
>

cc'ing Paolo in : I had an IRC chat with him and he has a very
interesting twist in the tale to add here.

> Maybe a naive question: why a "none" machine with zero RAM should fail to
> migrate ?

Assuming you are referring to why its failing ATM; it fails because
g_try_malloc0() inside bitmap_try_new() returns a NULL pointer for
zero bits and thus the check for NULL inside bitmap_new() becomes true
and it aborts. Check bitmap_new() for convenience.

Ignore the noise if you already knew this! :-)

Ashijeet