[RFC v2 13/21] mm: huge_mm: Make sure all split_huge_pmd calls are checked
From: Usama Arif <usama.arif@linux.dev>
Date: 2026-02-26 11:34:14
Also in:
linux-mm, linux-s390, lkml
Subsystem:
memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Mark __split_huge_pmd(), split_huge_pmd() and split_huge_pmd_address() with __must_check so the compiler warns if any caller ignores the return value. Not checking return value and operating on the basis that the pmd is split could result in a kernel bug. The possibility of an order-0 allocation failing for page table allocation is very low, but it should be handled correctly. Signed-off-by: Usama Arif <usama.arif@linux.dev> --- include/linux/huge_mm.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 207bf7cd95c78..b4c2fd4252097 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h@@ -419,7 +419,7 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped); void reparent_deferred_split_queue(struct mem_cgroup *memcg); #endif -int __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, +int __must_check __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address, bool freeze); /**
@@ -448,7 +448,7 @@ static inline bool pmd_is_huge(pmd_t pmd) return false; } -static inline int split_huge_pmd(struct vm_area_struct *vma, +static inline int __must_check split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address) { if (pmd_is_huge(*pmd))
@@ -456,7 +456,7 @@ static inline int split_huge_pmd(struct vm_area_struct *vma, return 0; } -int split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, +int __must_check split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, bool freeze); void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
--
2.47.3