[RFC PATCH v2 10/15] mm: Allow __pagetable_ctor() to fail
From: Kevin Brodsky <hidden>
Date: 2025-01-08 10:34:41
Also in:
linux-hardening, lkml
Subsystem:
generic include/asm header files, memory management - core, the rest · Maintainers:
Arnd Bergmann, Andrew Morton, David Hildenbrand, Linus Torvalds
In preparation for adding construction hooks (that may fail) to
__pagetable_ctor(), make __pagetable_ctor() return a bool,
propagate it to pagetable_*_ctor() and handle failure in
the generic {pud,p4d,pgd}_alloc.
Signed-off-by: Kevin Brodsky <redacted>
---
include/asm-generic/pgalloc.h | 15 ++++++++++++---
include/linux/mm.h | 21 ++++++++++-----------
2 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 892ece4558a2..9962f7454d0c 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h@@ -173,7 +173,10 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long if (!ptdesc) return NULL; - pagetable_pud_ctor(ptdesc); + if (!pagetable_pud_ctor(ptdesc)) { + pagetable_free(ptdesc); + return NULL; + } return ptdesc_address(ptdesc); } #define __pud_alloc_one(...) alloc_hooks(__pud_alloc_one_noprof(__VA_ARGS__))
@@ -227,7 +230,10 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long if (!ptdesc) return NULL; - pagetable_p4d_ctor(ptdesc); + if (!pagetable_p4d_ctor(ptdesc)) { + pagetable_free(ptdesc); + return NULL; + } return ptdesc_address(ptdesc); } #define __p4d_alloc_one(...) alloc_hooks(__p4d_alloc_one_noprof(__VA_ARGS__))
@@ -271,7 +277,10 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order if (!ptdesc) return NULL; - pagetable_pgd_ctor(ptdesc); + if (!pagetable_pgd_ctor(ptdesc)) { + pagetable_free(ptdesc); + return NULL; + } return ptdesc_address(ptdesc); } #define __pgd_alloc(...) alloc_hooks(__pgd_alloc_noprof(__VA_ARGS__))
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 453a26bcad1a..e99040be477f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -3076,12 +3076,13 @@ static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; } static inline void ptlock_free(struct ptdesc *ptdesc) {} #endif /* defined(CONFIG_SPLIT_PTE_PTLOCKS) */ -static inline void __pagetable_ctor(struct ptdesc *ptdesc) +static inline bool __pagetable_ctor(struct ptdesc *ptdesc) { struct folio *folio = ptdesc_folio(ptdesc); __folio_set_pgtable(folio); lruvec_stat_add_folio(folio, NR_PAGETABLE); + return true; } static inline void pagetable_dtor(struct ptdesc *ptdesc)
@@ -3103,8 +3104,7 @@ static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc) { if (!ptlock_init(ptdesc)) return false; - __pagetable_ctor(ptdesc); - return true; + return __pagetable_ctor(ptdesc); } pte_t *___pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp);
@@ -3210,8 +3210,7 @@ static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc) if (!pmd_ptlock_init(ptdesc)) return false; ptdesc_pmd_pts_init(ptdesc); - __pagetable_ctor(ptdesc); - return true; + return __pagetable_ctor(ptdesc); } /*
@@ -3233,19 +3232,19 @@ static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud) return ptl; } -static inline void pagetable_pud_ctor(struct ptdesc *ptdesc) +static inline bool pagetable_pud_ctor(struct ptdesc *ptdesc) { - __pagetable_ctor(ptdesc); + return __pagetable_ctor(ptdesc); } -static inline void pagetable_p4d_ctor(struct ptdesc *ptdesc) +static inline bool pagetable_p4d_ctor(struct ptdesc *ptdesc) { - __pagetable_ctor(ptdesc); + return __pagetable_ctor(ptdesc); } -static inline void pagetable_pgd_ctor(struct ptdesc *ptdesc) +static inline bool pagetable_pgd_ctor(struct ptdesc *ptdesc) { - __pagetable_ctor(ptdesc); + return __pagetable_ctor(ptdesc); } extern void __init pagecache_init(void);
--
2.47.0