From: Usama Arif <usama.arif@linux.dev>
To: Andrew Morton <akpm@linux-foundation.org>,
david@kernel.org, Lorenzo Stoakes <ljs@kernel.org>,
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: [v3 16/24] mm: huge_mm: Make sure all split_huge_pmd calls are checked
Date: Thu, 26 Mar 2026 19:08:58 -0700 [thread overview]
Message-ID: <20260327021403.214713-17-usama.arif@linux.dev> (raw)
In-Reply-To: <20260327021403.214713-1-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 224965fce4e66..c4d0badc4ce27 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -418,7 +418,7 @@ static inline int split_huge_page(struct page *page)
extern struct list_lru deferred_split_lru;
void deferred_split_folio(struct folio *folio, bool partially_mapped);
-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);
/**
@@ -447,7 +447,7 @@ 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))
@@ -455,7 +455,7 @@ 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,
--
2.52.0
next prev parent reply other threads:[~2026-03-27 2:15 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-27 2:08 [v3 00/24] mm: thp: lazy PTE page table allocation at PMD split time Usama Arif
2026-03-27 2:08 ` [v3 01/24] mm: thp: make split_huge_pmd functions return int for error propagation Usama Arif
2026-03-27 2:08 ` [v3 02/24] mm: thp: propagate split failure from vma_adjust_trans_huge() Usama Arif
2026-03-27 2:08 ` [v3 03/24] mm: thp: handle split failure in copy_huge_pmd() Usama Arif
2026-03-27 2:08 ` [v3 04/24] mm: thp: handle split failure in do_huge_pmd_wp_page() Usama Arif
2026-03-27 2:08 ` [v3 05/24] mm: thp: handle split failure in zap_pmd_range() Usama Arif
2026-03-27 2:08 ` [v3 06/24] mm: thp: handle split failure in wp_huge_pmd() Usama Arif
2026-03-27 2:08 ` [v3 07/24] mm: thp: retry on split failure in change_pmd_range() Usama Arif
2026-03-27 2:08 ` [v3 08/24] mm: thp: handle split failure in follow_pmd_mask() Usama Arif
2026-03-27 2:08 ` [v3 09/24] mm: handle walk_page_range() failure from THP split Usama Arif
2026-03-27 2:08 ` [v3 10/24] mm: thp: handle split failure in mremap move_page_tables() Usama Arif
2026-03-27 2:08 ` [v3 11/24] mm: thp: handle split failure in userfaultfd move_pages() Usama Arif
2026-03-27 2:08 ` [v3 12/24] mm: thp: handle split failure in device migration Usama Arif
2026-03-27 2:08 ` [v3 13/24] mm: proc: handle split_huge_pmd failure in pagemap_scan Usama Arif
2026-03-27 2:08 ` [v3 14/24] powerpc/mm: handle split_huge_pmd failure in subpage_prot Usama Arif
2026-03-27 2:08 ` [v3 15/24] fs/dax: handle split_huge_pmd failure in dax_iomap_pmd_fault Usama Arif
2026-03-27 2:08 ` Usama Arif [this message]
2026-03-27 2:08 ` [v3 17/24] mm: thp: allocate PTE page tables lazily at split time Usama Arif
2026-03-27 2:09 ` [v3 18/24] mm: thp: remove pgtable_trans_huge_{deposit/withdraw} when not needed Usama Arif
2026-03-27 2:09 ` [v3 19/24] mm: thp: add THP_SPLIT_PMD_FAILED counter Usama Arif
2026-03-27 2:09 ` [v3 20/24] selftests/mm: add THP PMD split test infrastructure Usama Arif
2026-03-27 2:09 ` [v3 21/24] selftests/mm: add partial_mprotect test for change_pmd_range Usama Arif
2026-03-27 2:09 ` [v3 22/24] selftests/mm: add partial_mlock test Usama Arif
2026-03-27 2:09 ` [v3 23/24] selftests/mm: add partial_mremap test for move_page_tables Usama Arif
2026-03-27 2:09 ` [v3 24/24] selftests/mm: add madv_dontneed_partial test Usama Arif
2026-03-27 8:51 ` [v3 00/24] mm: thp: lazy PTE page table allocation at PMD split time David Hildenbrand (Arm)
2026-03-27 9:25 ` Lorenzo Stoakes (Oracle)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260327021403.214713-17-usama.arif@linux.dev \
--to=usama.arif@linux.dev \
--cc=Liam.Howlett@oracle.com \
--cc=agordeev@linux.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=baohua@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=borntraeger@linux.ibm.com \
--cc=david@kernel.org \
--cc=dev.jain@arm.com \
--cc=fvdl@google.com \
--cc=gor@linux.ibm.com \
--cc=hannes@cmpxchg.org \
--cc=hca@linux.ibm.com \
--cc=kas@kernel.org \
--cc=kernel-team@meta.com \
--cc=lance.yang@linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=ljs@kernel.org \
--cc=maddy@linux.ibm.com \
--cc=mpe@ellerman.id.au \
--cc=npache@redhat.com \
--cc=riel@surriel.com \
--cc=ryan.roberts@arm.com \
--cc=shakeel.butt@linux.dev \
--cc=svens@linux.ibm.com \
--cc=vbabka@kernel.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox