Hi Sharyathi,
Thanks for both patch and test case.
The patch needs one more change I think.
The target buffer may be bigger, so the copy of the map needs
to be zero-extended.
Would you review it?
Thx.
-Cliff
> Date: Thu, 28 Jan 2010 11:23:05 +0530
> From: Sharyathi Nagesh <sharyath@xxxxxxxxxx>
> To: linux-numa@xxxxxxxxxxxxxxx, Andi Kleen <andi@xxxxxxxxxxxxxx>,
> Christoph Lameter <clameter@xxxxxxx>, Cliff Wickman <cpw@xxxxxxx>,
> Lee Schermerhorn <lee.schermerhorn@xxxxxx>,
> Amit K Arora <amitarora@xxxxxxxxxx>, deepti.kalra@xxxxxxxxxx
> Subject: Fix to numa_node_to_cpus_v2
>
> Hi
>
> We observed that numa_node_to_cpus api() api converts a node number to a
> bitmask of CPUs. The user must pass a long enough buffer. If the buffer is not
> long enough errno will be set to ERANGE and -1 returned. On success 0 is returned.
> This api has been changed in numa version 2.0. It has new implementation (_v2)
>
> Analysis:
> Now within the numa_node_to_cpus code there is a check if the size of buffer
> passed from the user matches the one returned by the sched_getaffinity. This
> check fails and hence we see "map size mismatch: abort" messages coming out on
> console. My system has 4 node and 8 CPUs.
>
> Testcase to reproduce the problem:
> #include <errno.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <numa.h>
>
> typedef unsigned long BUF[64];
>
> int numa_exit_on_error = 0;
>
> void node_to_cpus(void)
> {
> int i;
> BUF cpubuf;
> BUF affinityCPUs;
> int maxnode = numa_max_node();
> printf("available: %d nodes (0-%d)\n", 1+maxnode, maxnode);
> for (i = 0; i <= maxnode; i++) {
> printf("Calling numa_node_to_cpus()\n");
> printf("Size of BUF is : %d \n",sizeof(BUF));
> if ( 0 == numa_node_to_cpus(i, cpubuf, sizeof(BUF)) ) {
> printf("Calling numa_node_to_cpus() again \n");
> if ( 0 == numa_node_to_cpus(i, cpubuf, sizeof(BUF)) ) {
> } else {
> printf("Got < 0 \n");
> numa_error("numa_node_to_cpu");
> numa_exit_on_error = 1;
> exit(numa_exit_on_error);
> }
> } else {
> numa_error("numa_node_to_cpu 0");
> numa_exit_on_error = 1;
> exit(numa_exit_on_error);
> }
> }
> }
> int main()
> {
> void node_to_cpus();
> if (numa_available() < 0)
> {
> printf("This system does not support NUMA policy\n");
> numa_error("numa_available");
> numa_exit_on_error = 1;
> exit(numa_exit_on_error);
> }
> node_to_cpus();
> return numa_exit_on_error;
> }
> --------------------------------------------------------------------------------
>
> Problem Fix:
> The fix is to allow numa_node_to_cpus_v2() to fail only when the supplied
> buffer is smaller than the bitmask required to represent online NUMA nodes.
> Attaching the patch to address this issues, patch is generated against numactl-2.0.4-rc1
>
> Regards
> Yeehaw
>
---
libnuma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: numactl-dev/libnuma.c
===================================================================
--- numactl-dev.orig/libnuma.c
+++ numactl-dev/libnuma.c
@@ -1272,11 +1272,11 @@ numa_node_to_cpus_v2(int node, struct bi
if (node_cpu_mask_v2[node]) {
/* have already constructed a mask for this node */
- if (buffer->size != node_cpu_mask_v2[node]->size) {
+ if (buffer->size < node_cpu_mask_v2[node]->size) {
numa_error("map size mismatch; abort\n");
return -1;
}
- memcpy(buffer->maskp, node_cpu_mask_v2[node]->maskp, bufferlen);
+ copy_bitmask_to_bitmask(node_cpu_mask_v2[node], buffer);
return 0;
}
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