This is a note to let you know that I've just added the patch titled
x86/platform/uv: Use alternate source for socket to node data
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-platform-uv-use-alternate-source-for-socket-to-node-data.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5290e88ba2c742ca77c5f5b690e5af549cfd8591 Mon Sep 17 00:00:00 2001
From: Steve Wahl <steve.wahl@xxxxxxx>
Date: Mon, 7 Aug 2023 09:17:30 -0500
Subject: x86/platform/uv: Use alternate source for socket to node data
From: Steve Wahl <steve.wahl@xxxxxxx>
commit 5290e88ba2c742ca77c5f5b690e5af549cfd8591 upstream.
The UV code attempts to build a set of tables to allow it to do
bidirectional socket<=>node lookups.
But when nr_cpus is set to a smaller number than actually present, the
cpu_to_node() mapping information for unused CPUs is not available to
build_socket_tables(). This results in skipping some nodes or sockets
when creating the tables and leaving some -1's for later code to trip.
over, causing oopses.
The problem is that the socket<=>node lookups are created by doing a
loop over all CPUs, then looking up the CPU's APICID and socket. But
if a CPU is not present, there is no way to start this lookup.
Instead of looping over all CPUs, take CPUs out of the equation
entirely. Loop over all APICIDs which are mapped to a valid NUMA node.
Then just extract the socket-id from the APICID.
This avoid tripping over disabled CPUs.
Fixes: 8a50c5851927 ("x86/platform/uv: UV support for sub-NUMA clustering")
Signed-off-by: Steve Wahl <steve.wahl@xxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/20230807141730.1117278-1-steve.wahl%40hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/apic/x2apic_uv_x.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -1571,7 +1571,7 @@ static void __init build_socket_tables(v
{
struct uv_gam_range_entry *gre = uv_gre_table;
int nums, numn, nump;
- int cpu, i, lnid;
+ int i, lnid, apicid;
int minsock = _min_socket;
int maxsock = _max_socket;
int minpnode = _min_pnode;
@@ -1622,15 +1622,14 @@ static void __init build_socket_tables(v
/* Set socket -> node values: */
lnid = NUMA_NO_NODE;
- for_each_possible_cpu(cpu) {
- int nid = cpu_to_node(cpu);
- int apicid, sockid;
+ for (apicid = 0; apicid < ARRAY_SIZE(__apicid_to_node); apicid++) {
+ int nid = __apicid_to_node[apicid];
+ int sockid;
- if (lnid == nid)
+ if ((nid == NUMA_NO_NODE) || (lnid == nid))
continue;
lnid = nid;
- apicid = per_cpu(x86_cpu_to_apicid, cpu);
sockid = apicid >> uv_cpuid.socketid_shift;
if (_socket_to_node[sockid - minsock] == SOCK_EMPTY)
Patches currently in stable-queue which might be from steve.wahl@xxxxxxx are
queue-6.5/x86-platform-uv-use-alternate-source-for-socket-to-node-data.patch
