From 7190b3c8bd2b0cde483bd440cf91ba1c518b4261 Mon Sep 17 00:00:00 2001 From: Ignacio Moreno Gonzalez Date: Wed, 7 May 2025 15:28:06 +0200 Subject: [PATCH] mm: mmap: map MAP_STACK to VM_NOHUGEPAGE only if THP is enabled commit c4608d1bf7c6 ("mm: mmap: map MAP_STACK to VM_NOHUGEPAGE") maps the mmap option MAP_STACK to VM_NOHUGEPAGE. This is also done if CONFIG_TRANSPARENT_HUGEPAGE is not defined. But in that case, the VM_NOHUGEPAGE does not make sense. I discovered this issue when trying to use the tool CRIU to checkpoint and restore a container. Our running kernel is compiled without CONFIG_TRANSPARENT_HUGEPAGE. CRIU parses the output of /proc//smaps and saves the "nh" flag. When trying to restore the container, CRIU fails to restore the "nh" mappings, since madvise() MADV_NOHUGEPAGE always returns an error because CONFIG_TRANSPARENT_HUGEPAGE is not defined. Link: https://lkml.kernel.org/r/20250507-map-map_stack-to-vm_nohugepage-only-if-thp-is-enabled-v5-1-c6c38cfefd6e@kuka.com Fixes: c4608d1bf7c6 ("mm: mmap: map MAP_STACK to VM_NOHUGEPAGE") Signed-off-by: Ignacio Moreno Gonzalez Acked-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes Reviewed-by: Yang Shi Reviewed-by: Liam R. Howlett Cc: Signed-off-by: Andrew Morton --- include/linux/mman.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/mman.h b/include/linux/mman.h index bce214fece16..f4c6346a8fcd 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -155,7 +155,9 @@ calc_vm_flag_bits(struct file *file, unsigned long flags) return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | +#ifdef CONFIG_TRANSPARENT_HUGEPAGE _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | +#endif arch_calc_vm_flag_bits(file, flags); }