FAILED: patch "[PATCH] LoongArch: Don't init & online empty nodes" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] LoongArch: Don't init & online empty nodes" failed to apply to 6.12-stable tree

[Sasha Levin]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 87c6d144bc7bbed0c4573848b9c92006edca7848
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107052654-failed-6.12-87c6d144bc7b@kernel.org' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 87c6d144bc7bbed0c4573848b9c92006edca7848 Mon Sep 17 00:00:00 2001
From: Huacai Chen <chenhuacai@loongson.cn>
Date: Tue, 27 Oct 2026 22:51:23 +0800
Subject: [PATCH] LoongArch: Don't init & online empty nodes

Don't init & online empty nodes without any CPU cores (and memory), in
this way "lscpu" will not display confusing empty nodes.

Modify fake_numa_init() to make sure at least Node-0 isn't empty for the
FDT booting case.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 arch/loongarch/kernel/numa.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index c96c536237151..7dedc134ddfe0 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -216,6 +216,8 @@ static int __init fake_numa_init(void)
 	phys_addr_t start = memblock_start_of_DRAM();
 	phys_addr_t end = memblock_end_of_DRAM() - 1;
 
+	set_cpuid_to_node(0, 0);
+	early_numa_add_cpu(0, 0);
 	pr_info("Faking a node at [mem %pap-%pap]\n", &start, &end);
 
 	return numa_add_memblk(0, start, end + 1);
@@ -244,8 +246,10 @@ int __init init_numa_memory(void)
 		return -EINVAL;
 
 	for_each_node_mask(node, node_possible_map) {
-		node_mem_init(node);
-		node_set_online(node);
+		if (!cpumask_empty(&cpus_on_node[node])) {
+			node_mem_init(node);
+			node_set_online(node);
+		}
 	}
 	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
 	max_low_pfn = min(PFN_DOWN(HIGHMEM_START), max_pfn);
-- 
2.53.0

[PATCH 6.12.y 1/2] LoongArch: remove redundant numa_nodes_parsed node_set()

[Sasha Levin]

From: Sang-Heon Jeon <ekffu200098@gmail.com>

[ Upstream commit 3aeac07c5b1c3399487f4b38182f8cfbc3dbbd53 ]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Link: https://patch.msgid.link/20260703041329.2797584-7-ekffu200098@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Stable-dep-of: 87c6d144bc7b ("LoongArch: Don't init & online empty nodes")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/loongarch/kernel/numa.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index 84fe7f8548209..aefe9984be794 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -318,7 +318,6 @@ static int __init fake_numa_init(void)
 	phys_addr_t start = memblock_start_of_DRAM();
 	phys_addr_t end = memblock_end_of_DRAM() - 1;
 
-	node_set(0, numa_nodes_parsed);
 	pr_info("Faking a node at [mem %pap-%pap]\n", &start, &end);
 
 	return numa_add_memblk(0, start, end + 1);
-- 
2.53.0

[PATCH 6.12.y 2/2] LoongArch: Don't init & online empty nodes

[Sasha Levin]

From: Huacai Chen <chenhuacai@loongson.cn>

[ Upstream commit 87c6d144bc7bbed0c4573848b9c92006edca7848 ]

Don't init & online empty nodes without any CPU cores (and memory), in
this way "lscpu" will not display confusing empty nodes.

Modify fake_numa_init() to make sure at least Node-0 isn't empty for the
FDT booting case.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/loongarch/kernel/numa.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index aefe9984be794..7c0ae91cb395f 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -318,6 +318,8 @@ static int __init fake_numa_init(void)
 	phys_addr_t start = memblock_start_of_DRAM();
 	phys_addr_t end = memblock_end_of_DRAM() - 1;
 
+	set_cpuid_to_node(0, 0);
+	early_numa_add_cpu(0, 0);
 	pr_info("Faking a node at [mem %pap-%pap]\n", &start, &end);
 
 	return numa_add_memblk(0, start, end + 1);
@@ -352,8 +354,10 @@ int __init init_numa_memory(void)
 		return -EINVAL;
 
 	for_each_node_mask(node, node_possible_map) {
-		node_mem_init(node);
-		node_set_online(node);
+		if (!cpumask_empty(&cpus_on_node[node])) {
+			node_mem_init(node);
+			node_set_online(node);
+		}
 	}
 	max_low_pfn = PHYS_PFN(memblock_end_of_DRAM());
 
-- 
2.53.0