[PATCH v6 07/39] mm: assert mmap lock held, use new flags API in vm_insert_page[s]
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From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-10-13 15:09:56
Also in:
bpf, dri-devel, fuse-devel, kvm, kvmarm, linux-arch, linux-doc, linux-fbdev, linux-fsdevel, linux-mm, linux-perf-users, linux-rdma, linux-riscv, linux-s390, linux-scsi, linux-sound, linux-trace-kernel, linux-usb, lkml, selinux, sparclinux
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Revision v6 of 6 in this series; queued in linux-next as 2fd8d5b9bf9a on 2026-10-21.
Revisions (6)
The existing logic asserts that an mmap write lock is held, bizarrely, by asserting that an mmap_read_trylock() fails (which is not the same thing). Assert the mmap write lock here and switch to using the new VMA flags API while here. Note that the vma_start_write() is explicitly broken out from vm_flags_set() here in order to use vma_set_flags() safely. Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org> --- mm/memory.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 448342883e9d..a35cca09eb71 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -2599,10 +2599,11 @@ int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, if (!range_in_vma(vma, addr, end)) return -EFAULT; - if (!(vma->vm_flags & VM_MIXEDMAP)) { - VM_WARN_ON_ONCE(mmap_read_trylock(vma->vm_mm)); - VM_WARN_ON_ONCE(vma->vm_flags & VM_PFNMAP); - vm_flags_set(vma, VM_MIXEDMAP); + if (!vma_test(vma, VMA_MIXEDMAP_BIT)) { + mmap_assert_write_locked(vma->vm_mm); + VM_WARN_ON_ONCE(vma_test(vma, VMA_PFNMAP_BIT)); + vma_start_write(vma); + vma_set_flags(vma, VMA_MIXEDMAP_BIT); } /* Defer page refcount checking till we're about to map that page. */ return insert_pages(vma, addr, pages, num, vma->vm_page_prot);
@@ -2675,10 +2676,11 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, { if (addr < vma->vm_start || addr >= vma->vm_end) return -EFAULT; - if (!(vma->vm_flags & VM_MIXEDMAP)) { - BUG_ON(mmap_read_trylock(vma->vm_mm)); - BUG_ON(vma->vm_flags & VM_PFNMAP); - vm_flags_set(vma, VM_MIXEDMAP); + if (!vma_test(vma, VMA_MIXEDMAP_BIT)) { + mmap_assert_write_locked(vma->vm_mm); + VM_WARN_ON_ONCE(vma_test(vma, VMA_PFNMAP_BIT)); + vma_start_write(vma); + vma_set_flags(vma, VMA_MIXEDMAP_BIT); } return insert_page(vma, addr, page, vma->vm_page_prot, false); }
--
2.55.0