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authorSuren Baghdasaryan <surenb@google.com>2023-08-04 18:27:22 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-08-21 23:37:46 +0300
commit60081bf19b0ec8fa40c589bd361fa2bc763f1050 (patch)
treeb4c4909b23e49edc487efcd44d983fb2f2af6334 /arch
parente727bfd5e73a35ecbc4a01a15c659b9fafaa97c0 (diff)
downloadlinux-60081bf19b0ec8fa40c589bd361fa2bc763f1050.tar.xz
mm: lock vma explicitly before doing vm_flags_reset and vm_flags_reset_once
Implicit vma locking inside vm_flags_reset() and vm_flags_reset_once() is not obvious and makes it hard to understand where vma locking is happening. Also in some cases (like in dup_userfaultfd()) vma should be locked earlier than vma_flags modification. To make locking more visible, change these functions to assert that the vma write lock is taken and explicitly lock the vma beforehand. Fix userfaultfd functions which should lock the vma earlier. Link: https://lkml.kernel.org/r/20230804152724.3090321-5-surenb@google.com Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kvm/book3s_hv_uvmem.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 709ebd578394..e2d6f9327f77 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -410,6 +410,7 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm,
ret = H_STATE;
break;
}
+ vma_start_write(vma);
/* Copy vm_flags to avoid partial modifications in ksm_madvise */
vm_flags = vma->vm_flags;
ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,