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authorDmitry Safonov2020-12-14 19:08:25 -0800
committerLinus Torvalds2020-12-15 12:13:41 -0800
commit871402e05b24cb56bc69df47cff960d0e0d24267 (patch)
treef8235ea5b089ed3c9def2e9c6ed2df51d205e8d3 /arch/x86
parent73d5e06299195f4df82832cfc4a3a0c574c1e473 (diff)
mm: forbid splitting special mappings
Don't allow splitting of vm_special_mapping's. It affects vdso/vvar areas. Uprobes have only one page in xol_area so they aren't affected. Those restrictions were enforced by checks in .mremap() callbacks. Restrict resizing with generic .split() callback. Link: https://lkml.kernel.org/r/20201013013416.390574-7-dima@arista.com Signed-off-by: Dmitry Safonov <dima@arista.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Geffon <bgeffon@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/entry/vdso/vma.c17
1 files changed, 0 insertions, 17 deletions
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 9185cb1d13b9..0c942b31825d 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -89,30 +89,14 @@ static void vdso_fix_landing(const struct vdso_image *image,
static int vdso_mremap(const struct vm_special_mapping *sm,
struct vm_area_struct *new_vma)
{
- unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
const struct vdso_image *image = current->mm->context.vdso_image;
- if (image->size != new_size)
- return -EINVAL;
-
vdso_fix_landing(image, new_vma);
current->mm->context.vdso = (void __user *)new_vma->vm_start;
return 0;
}
-static int vvar_mremap(const struct vm_special_mapping *sm,
- struct vm_area_struct *new_vma)
-{
- const struct vdso_image *image = new_vma->vm_mm->context.vdso_image;
- unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
-
- if (new_size != -image->sym_vvar_start)
- return -EINVAL;
-
- return 0;
-}
-
#ifdef CONFIG_TIME_NS
static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
{
@@ -252,7 +236,6 @@ static const struct vm_special_mapping vdso_mapping = {
static const struct vm_special_mapping vvar_mapping = {
.name = "[vvar]",
.fault = vvar_fault,
- .mremap = vvar_mremap,
};
/*