From 5528f9132cf65d4d892bcbc5684c61e7822b21e9 Mon Sep 17 00:00:00 2001 From: Linus Torvalds <torvalds@linux-foundation.org> Date: Fri, 13 Aug 2010 09:24:04 -0700 Subject: mm: fix missing page table unmap for stack guard page failure case From: Linus Torvalds <torvalds@linux-foundation.org> commit 5528f9132cf65d4d892bcbc5684c61e7822b21e9 upstream. .. which didn't show up in my tests because it's a no-op on x86-64 and most other architectures. But we enter the function with the last-level page table mapped, and should unmap it at exit. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- mm/memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/memory.c +++ b/mm/memory.c @@ -2783,8 +2783,10 @@ static int do_anonymous_page(struct mm_s spinlock_t *ptl; pte_t entry; - if (check_stack_guard_page(vma, address) < 0) + if (check_stack_guard_page(vma, address) < 0) { + pte_unmap(page_table); return VM_FAULT_SIGBUS; + } if (!(flags & FAULT_FLAG_WRITE)) { entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),