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.

Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
---
 arch/x86/kernel/apic/x2apic_uv_x.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 15209f220e1f..daf9853f7868 100644
--- 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(void)
 		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 == (int)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)
-- 
2.43.0

On Tue, Mar 10, 2026 at 05:49:57PM -0500, Kyle Meyer wrote:
> When a socket is deconfigured, it's mapped to SOCK_EMPTY (0xffff). This
> causes a panic while allocating UV hub info structures.

This sounds like this needs to be CC:stable, have a Fixes: tag and so on, and
go in now?

Right?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

On Fri, Mar 20, 2026 at 04:42:32PM +0100, Borislav Petkov wrote:
> On Tue, Mar 10, 2026 at 05:49:57PM -0500, Kyle Meyer wrote:
> > When a socket is deconfigured, it's mapped to SOCK_EMPTY (0xffff). This
> > causes a panic while allocating UV hub info structures.
> 
> This sounds like this needs to be CC:stable, have a Fixes: tag and so on, and
> go in now?
> 
> Right?

Yes, thank you. I'll send a v2.

Thanks,
Kyle Meyer

On Tue, Mar 10, 2026 at 05:49:57PM -0500, Kyle Meyer wrote:
> 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.
> 
> Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>

Reviewed-by: Steve Wahl <steve.wahl@hpe.com>

> ---
>  arch/x86/kernel/apic/x2apic_uv_x.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
> index 15209f220e1f..daf9853f7868 100644
> --- 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(void)
>  		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 == (int)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)
> -- 
> 2.43.0
> 

-- 
Steve Wahl, Hewlett Packard Enterprise