[PATCH 6.19 196/220] x86/platform/uv: Handle deconfigured sockets

Greg Kroah-Hartman
2026-03-23T13:59:30Z

From: Kyle Meyer <kyle.meyer@hpe.com>

commit 1f6aa5bbf1d0f81a8a2aafc16136e7dd9a609ff3 upstream.

When a socket is deconfigured, it's mapped to SOCK_EMPTY (0xffff). This causes
a panic while allocating UV hub info structures.

Fix this by using NUMA_NO_NODE, allowing UV hub info structures to be
allocated on valid nodes.

Fixes: 8a50c5851927 ("x86/platform/uv: UV support for sub-NUMA clustering")
Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/ab2BmGL0ehVkkjKk@hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/apic/x2apic_uv_x.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -1708,8 +1708,22 @@ static void __init uv_system_init_hub(vo
struct uv_hub_info_s *new_hub;

/* Allocate & fill new per hub info list */
- new_hub = (bid == 0) ? &uv_hub_info_node0
- : kzalloc_node(bytes, GFP_KERNEL, uv_blade_to_node(bid));
+ if (bid == 0) {
+ new_hub = &uv_hub_info_node0;
+ } else {
+ int nid;
+
+ /*
+ * Deconfigured sockets are mapped to SOCK_EMPTY. Use
+ * NUMA_NO_NODE to allocate on a valid node.
+ */
+ nid = uv_blade_to_node(bid);
+ if (nid == SOCK_EMPTY)
+ nid = NUMA_NO_NODE;
+
+ new_hub = kzalloc_node(bytes, GFP_KERNEL, nid);
+ }
+
if (WARN_ON_ONCE(!new_hub)) {
/* do not kfree() bid 0, which is statically allocated */
while (--bid > 0)