Hi Jens, I got some unexpected results with this patch this morning.
When loading null_blk with no arguments, I got the invalid home_node
value error message. I did some debug and found that the values
seemed fine:
+ pr_err("g_home_node is %d", g_home_node);
+ pr_err("nr_online_nodes is %d", nr_online_nodes);
+ pr_err("NUMA_NO_NODE is %d", NUMA_NO_NODE);
+
+ if (g_home_node >= nr_online_nodes) {
+ pr_err("null_blk: invalid home_node value\n");
+ g_home_node = NUMA_NO_NODE;
+ }
+
if (g_queue_mode == NULL_Q_RQ) {
pr_err("null_blk: legacy IO path no longer available\n");
return -EINVAL;
[root@localhost linux]# modprobe null_blk
[ 296.336473] g_home_node is -1
[ 296.336474] nr_online_nodes is 1
[ 296.336514] NUMA_NO_NODE is -1
[ 296.336558] null_blk: invalid home_node value
[ 296.338825] null: module loaded
[root@localhost linux]# numactl --hardware
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 828 MB
node 0 free: 451 MB
node distances:
node 0
0: 10
Fortunately, and also unexpectedly to me, I was able to fix the issue
just by casting nr_online_nodes as an int.
+ if (g_home_node >= (int)nr_online_nodes) {
+ pr_err("null_blk: invalid home_node value\n");
+ g_home_node = NUMA_NO_NODE;
+ }
+
Would you like me to send in a v2 for this?
Thanks.
On Fri, Apr 5, 2019 at 6:22 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> On 4/5/19 3:42 PM, John Pittman wrote:
> > At module load, if the selected home_node value is greater than
> > the available numa nodes, the system will crash in
> > __alloc_pages_nodemask() due to a bad paging request. Prevent this
> > user error crash by detecting the bad value, logging an error, and
> > setting g_home_node back to the default of NUMA_NO_NODE.
>
> Applied, thanks.
>
> --
> Jens Axboe
>
