From 03fdc2c277afdbd217eccd1ce0cfeff77ebd8b77 Mon Sep 17 00:00:00 2001 From: Chuck Ebbert <76306.1226@compuserve.com> Date: Mon, 26 Jun 2006 13:59:50 +0200 Subject: [PATCH] [PATCH] x86_64: enlarge window for stack growth Allow stack growth so the 'enter' instruction works. Also fixes problem in compat_sys_kexec_load() which could allocate more than 128 bytes using compat_alloc_user_space(). Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/mm/fault.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c index 64728898f869..4968a71df4aa 100644 --- a/arch/x86_64/mm/fault.c +++ b/arch/x86_64/mm/fault.c @@ -410,8 +410,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, if (!(vma->vm_flags & VM_GROWSDOWN)) goto bad_area; if (error_code & 4) { - // XXX: align red zone size with ABI - if (address + 128 < regs->rsp) + /* Allow userspace just enough access below the stack pointer + * to let the 'enter' instruction work. + */ + if (address + 65536 + 32 * sizeof(unsigned long) < regs->rsp) goto bad_area; } if (expand_stack(vma, address))