On 3/18/25 12:49, Wei Yang wrote:

Commit 61167ad5fecd ("mm: pass nid to reserve_bootmem_region()") introduce a way to set nid to all reserved region.

But there is a corner case it will leave some region with invalid nid. When memblock_set_node() doubles the array of memblock.reserved, it may lead to a new reserved region before current position. The new region will be left with an invalid node id.

But is it really possible for the memblock array to double during memmap_init_reserved_pages() ? Just wondering - could you please give some example scenarios.

Repeat the process when detecting it.

Fixes: 61167ad5fecd ("mm: pass nid to reserve_bootmem_region()") Signed-off-by: Wei Yang richard.weiyang@gmail.com CC: Mike Rapoport rppt@kernel.org CC: Yajun Deng yajun.deng@linux.dev CC: stable@vger.kernel.org

---

v2: move check out side of the loop

mm/memblock.c | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/mm/memblock.c b/mm/memblock.c index 85442f1b7f14..0bae7547d2db 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -2179,11 +2179,14 @@ static void __init memmap_init_reserved_pages(void) struct memblock_region *region; phys_addr_t start, end; int nid;

• unsigned long max_reserved;

/* * set nid on all reserved pages and also treat struct * pages for the NOMAP regions as PageReserved */ +repeat:

• max_reserved = memblock.reserved.max; for_each_mem_region(region) { nid = memblock_get_region_node(region); start = region->base;

@@ -2194,6 +2197,13 @@ static void __init memmap_init_reserved_pages(void) memblock_set_node(start, region->size, &memblock.reserved, nid); }

• /*

• * 'max' is changed means memblock.reserved has been doubled its
  

• * array, which may result a new reserved region before current
  

• * 'start'. Now we should repeat the procedure to set its node id.
  

• */
  

• if (max_reserved != memblock.reserved.max)

• goto repeat;
  

/* * initialize struct pages for reserved regions that don't have