From: Usama Arif <usama.arif@linux.dev>
To: Andrew Morton <akpm@linux-foundation.org>,
david@kernel.org, lorenzo.stoakes@oracle.com,
willy@infradead.org, linux-mm@kvack.org
Cc: fvdl@google.com, hannes@cmpxchg.org, riel@surriel.com,
shakeel.butt@linux.dev, kas@kernel.org, baohua@kernel.org,
dev.jain@arm.com, baolin.wang@linux.alibaba.com,
npache@redhat.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com,
Vlastimil Babka <vbabka@kernel.org>,
lance.yang@linux.dev, linux-kernel@vger.kernel.org,
kernel-team@meta.com, maddy@linux.ibm.com, mpe@ellerman.id.au,
linuxppc-dev@lists.ozlabs.org, hca@linux.ibm.com,
gor@linux.ibm.com, agordeev@linux.ibm.com,
borntraeger@linux.ibm.com, svens@linux.ibm.com,
linux-s390@vger.kernel.org, Usama Arif <usama.arif@linux.dev>
Subject: [RFC v2 13/21] mm: huge_mm: Make sure all split_huge_pmd calls are checked
Date: Thu, 26 Feb 2026 03:23:42 -0800 [thread overview]
Message-ID: <20260226113233.3987674-14-usama.arif@linux.dev> (raw)
In-Reply-To: <20260226113233.3987674-1-usama.arif@linux.dev>
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
next prev parent reply other threads:[~2026-02-26 11:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-26 11:23 [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split Usama Arif
2026-02-26 11:23 ` [RFC v2 01/21] mm: thp: make split_huge_pmd functions return int for error propagation Usama Arif
2026-02-26 11:23 ` [RFC v2 02/21] mm: thp: propagate split failure from vma_adjust_trans_huge() Usama Arif
2026-02-26 11:23 ` [RFC v2 03/21] mm: thp: handle split failure in copy_huge_pmd() Usama Arif
2026-02-26 11:23 ` [RFC v2 04/21] mm: thp: handle split failure in do_huge_pmd_wp_page() Usama Arif
2026-02-26 11:23 ` [RFC v2 05/21] mm: thp: handle split failure in zap_pmd_range() Usama Arif
2026-02-26 11:23 ` [RFC v2 06/21] mm: thp: handle split failure in wp_huge_pmd() Usama Arif
2026-02-26 11:23 ` [RFC v2 07/21] mm: thp: retry on split failure in change_pmd_range() Usama Arif
2026-02-26 11:23 ` [RFC v2 08/21] mm: thp: handle split failure in follow_pmd_mask() Usama Arif
2026-02-26 11:23 ` [RFC v2 09/21] mm: handle walk_page_range() failure from THP split Usama Arif
2026-02-26 11:23 ` [RFC v2 10/21] mm: thp: handle split failure in mremap move_page_tables() Usama Arif
2026-02-26 11:23 ` [RFC v2 11/21] mm: thp: handle split failure in userfaultfd move_pages() Usama Arif
2026-02-26 11:23 ` [RFC v2 12/21] mm: thp: handle split failure in device migration Usama Arif
2026-02-26 11:23 ` Usama Arif [this message]
2026-02-26 11:23 ` [RFC v2 14/21] mm: thp: allocate PTE page tables lazily at split time Usama Arif
2026-02-26 11:23 ` [RFC v2 15/21] mm: thp: remove pgtable_trans_huge_{deposit/withdraw} when not needed Usama Arif
2026-02-26 11:23 ` [RFC v2 16/21] mm: thp: add THP_SPLIT_PMD_FAILED counter Usama Arif
2026-02-26 14:22 ` Usama Arif
2026-02-26 11:23 ` [RFC v2 17/21] selftests/mm: add THP PMD split test infrastructure Usama Arif
2026-02-26 11:23 ` [RFC v2 18/21] selftests/mm: add partial_mprotect test for change_pmd_range Usama Arif
2026-02-26 11:23 ` [RFC v2 19/21] selftests/mm: add partial_mlock test Usama Arif
2026-02-26 11:23 ` [RFC v2 20/21] selftests/mm: add partial_mremap test for move_page_tables Usama Arif
2026-02-26 11:23 ` [RFC v2 21/21] selftests/mm: add madv_dontneed_partial test Usama Arif
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