It's currently only used in the EFI code, which is safe AFAICT. Warn if anyone tries to use it on the normal kernel pgd.
Signed-off-by: Andy Lutomirski <[email protected]> --- arch/x86/mm/pageattr.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 6a8026918bf6..e9b9c5cedbb8 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1996,6 +1996,9 @@ out: void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, unsigned numpages) { + /* Unmapping kernel entries from init_mm's pgd is not allowed. */ + WARN_ON(root == init_mm.pgd); + unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT)); } -- 2.7.4
