From: Hannes Reinecke Date: Tue, 29 Jul 2025 06:46:34 +0000 (+0200) Subject: drivers/base/memory: add node id parameter to add_memory_block() X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c6a809363a66b8ff0f6a000b5f09408a1b33eeb5;p=thirdparty%2Fkernel%2Fstable.git drivers/base/memory: add node id parameter to add_memory_block() Patch series "mm/memory_hotplug: fixup crash during uevent handling", v4. we have some udev rules trying to read the sysfs attribute 'valid_zones' during an memory 'add' event, causing a crash in zone_for_pfn_range(). Debugging found that mem->nid was set to NUMA_NO_NODE, which crashed in NODE_DATA(nid). Further analysis revealed that we're running into a race with udev event processing: add_memory_resource() has this function calls: 1) __try_online_node() 2) arch_add_memory() 3) create_memory_block_devices() -> calls device_register() -> memory 'add' event 4) node_set_online()/__register_one_node() -> calls device_register() -> node 'add' event 5) register_memory_blocks_under_node() -> sets mem->nid Which, to the uninitated, is ... weird ... Why do we try to online the node in 1), but only register the node in 4) _after_ we have created the memory blocks in 3) ? And why do we set the 'nid' value in 5), when the uevent (which might need to see the correct 'nid' value) is sent out in 3) ? There must be a reason, I'm sure ... So here's a small patchset to fixup uevent ordering. The first patch adds a 'nid' parameter to add_memory_blocks() (to avoid mem->nid being initialized with NUMA_NO_NODE), and the second patch reshuffles the code in add_memory_resource() to fully initialize the node prior to calling create_memory_block_devices() so that the node is valid at that time and uevent processing will see correct values in sysfs. This patch (of 3): We have some udev rules trying to read the sysfs attribute 'valid_zones' during an memory 'add' event, causing a crash in zone_for_pfn_range(). Debugging found that mem->nid was set to NUMA_NO_NODE, which crashed in NODE_DATA(nid). Further analysis revealed that we're running into a race with udev event processing: add_memory_resource() has this function calls: 1) __try_online_node() 2) arch_add_memory() 3) create_memory_block_devices() -> calls device_register() -> memory 'add' event 4) node_set_online()/__register_one_node() -> calls device_register() -> node 'add' event 5) register_memory_blocks_under_node() -> sets mem->nid Which, to the uninitated, is ... weird ... Why do we try to online the node in 1), but only register the node in 4) _after_ we have created the memory blocks in 3) ? And why do we set the 'nid' value in 5), when the uevent (which might need to see the correct 'nid' value) is sent out in 3) ? There must be a reason, I'm sure ... So here's a small patchset to fixup uevent ordering. The first patch adds a 'nid' parameter to add_memory_blocks() (to avoid mem->nid being initialized with NUMA_NO_NODE), and the second patch reshuffles the code in add_memory_resource() to fully initialize the node prior to calling create_memory_block_devices() so that the node is valid at that time and uevent processing will see correct values in sysfs. This patch (of 3): Add a 'nid' parameter to add_memory_block() to initialize the memory block with the correct node id. Link: https://lkml.kernel.org/r/20250729064637.51662-1-hare@kernel.org Link: https://lkml.kernel.org/r/20250729064637.51662-2-hare@kernel.org Signed-off-by: Hannes Reinecke Acked-by: David Hildenbrand Acked-by: Oscar Salvador Reviewed-by: Donet Tom Signed-off-by: Andrew Morton --- diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 5c6c1d6bb59f1..894d3891292bf 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -809,7 +809,7 @@ void memory_block_add_nid(struct memory_block *mem, int nid, } #endif -static int add_memory_block(unsigned long block_id, unsigned long state, +static int add_memory_block(unsigned long block_id, int nid, unsigned long state, struct vmem_altmap *altmap, struct memory_group *group) { @@ -827,7 +827,7 @@ static int add_memory_block(unsigned long block_id, unsigned long state, mem->start_section_nr = block_id * sections_per_block; mem->state = state; - mem->nid = NUMA_NO_NODE; + mem->nid = nid; mem->altmap = altmap; INIT_LIST_HEAD(&mem->group_next); @@ -854,13 +854,6 @@ static int add_memory_block(unsigned long block_id, unsigned long state, return 0; } -static int add_hotplug_memory_block(unsigned long block_id, - struct vmem_altmap *altmap, - struct memory_group *group) -{ - return add_memory_block(block_id, MEM_OFFLINE, altmap, group); -} - static void remove_memory_block(struct memory_block *memory) { if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys)) @@ -900,7 +893,7 @@ int create_memory_block_devices(unsigned long start, unsigned long size, return -EINVAL; for (block_id = start_block_id; block_id != end_block_id; block_id++) { - ret = add_hotplug_memory_block(block_id, altmap, group); + ret = add_memory_block(block_id, NUMA_NO_NODE, MEM_OFFLINE, altmap, group); if (ret) break; } @@ -1005,7 +998,7 @@ void __init memory_dev_init(void) continue; block_id = memory_block_id(nr); - ret = add_memory_block(block_id, MEM_ONLINE, NULL, NULL); + ret = add_memory_block(block_id, NUMA_NO_NODE, MEM_ONLINE, NULL, NULL); if (ret) { panic("%s() failed to add memory block: %d\n", __func__, ret);