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authorDmitry Safonov <dima@arista.com>2020-12-14 19:08:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:41 -0800
commit871402e05b24cb56bc69df47cff960d0e0d24267 (patch)
treef8235ea5b089ed3c9def2e9c6ed2df51d205e8d3 /arch/mips/vdso
parent73d5e06299195f4df82832cfc4a3a0c574c1e473 (diff)
downloadlinux-871402e05b24cb56bc69df47cff960d0e0d24267.tar.gz
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/mips/vdso')
-rw-r--r--arch/mips/vdso/genvdso.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/mips/vdso/genvdso.c b/arch/mips/vdso/genvdso.c
index abb06ae04b40..09e30eb4be86 100644
--- a/arch/mips/vdso/genvdso.c
+++ b/arch/mips/vdso/genvdso.c
@@ -263,10 +263,6 @@ int main(int argc, char **argv)
 	fprintf(out_file, "	const struct vm_special_mapping *sm,\n");
 	fprintf(out_file, "	struct vm_area_struct *new_vma)\n");
 	fprintf(out_file, "{\n");
-	fprintf(out_file, "	unsigned long new_size =\n");
-	fprintf(out_file, "	new_vma->vm_end - new_vma->vm_start;\n");
-	fprintf(out_file, "	if (vdso_image.size != new_size)\n");
-	fprintf(out_file, "		return -EINVAL;\n");
 	fprintf(out_file, "	current->mm->context.vdso =\n");
 	fprintf(out_file, "	(void *)(new_vma->vm_start);\n");
 	fprintf(out_file, "	return 0;\n");