On 9/30/20 6:54 AM, Michal Privoznik wrote:

After v6.5.0-rc1~148 we started to rectify vCPU to guest NUMA assignment - if there is a vCPU not assigned to any guest NUMA node it is automatically assigned to node #0.

A month later I've made it possible to define guest NUMA nodes without vCPUs (v6.6.0-rc1~250) - this is needed because of HMAT. As a part of that I fixed all callers of virDomainNumaGetNodeCpumask() (which returns a bitmap of vCPUs for given node) to handle case when NULL is returned (i.e. no vCPUs assigned to given node). But of course my patch was written before aforementioned vCPU rectify patch but merged afterwards and hence I missed the virDomainNumaFillCPUsInNode() caller.

And because we are dealing with a NULL pointer, of course this leads to a crash. Just try to define a domain with at least two NUMA nodes and no vCPU assignment to any of the nodes.

Well, I wrote v6.5.0-rc1~148 and reviewed v6.6.0-rc1~250, and didn't see this coming either. Hopefully we'll redeem ourselves now :)

Fixes: a26f61ee0cffa421b87ef568002b684dd8025432 Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1880289 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> ---

Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>

src/conf/numa_conf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/conf/numa_conf.c b/src/conf/numa_conf.c index bfa312215c..cc6c77f105 100644 --- a/src/conf/numa_conf.c +++ b/src/conf/numa_conf.c @@ -1816,7 +1816,7 @@ virDomainNumaFillCPUsInNode(virDomainNumaPtr numa, for (i = 0; i < numa->nmem_nodes; i++) { virBitmapPtr nodeCpus = virDomainNumaGetNodeCpumask(numa, i);

- if (i == node) + if (i == node || !nodeCpus) continue;

virBitmapSubtract(maxCPUsBitmap, nodeCpus);