From 9be260a646bf76fa418ee519afa10196b3164681 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 5 Feb 2009 17:12:39 -0500 Subject: [PATCH] prevent kprobes from catching spurious page faults Prevent kprobes from catching spurious faults which will cause infinite recursive page-fault and memory corruption by stack overflow. Signed-off-by: Masami Hiramatsu Cc: [2.6.28.x] Signed-off-by: Linus Torvalds --- arch/x86/mm/fault.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 90dfae511a4..c76ef1d701c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -603,8 +603,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) si_code = SEGV_MAPERR; - if (notify_page_fault(regs)) - return; if (unlikely(kmmio_fault(regs, address))) return; @@ -634,6 +632,9 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) if (spurious_fault(address, error_code)) return; + /* kprobes don't want to hook the spurious faults. */ + if (notify_page_fault(regs)) + return; /* * Don't take the mm semaphore here. If we fixup a prefetch * fault we could otherwise deadlock. @@ -641,6 +642,9 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) goto bad_area_nosemaphore; } + /* kprobes don't want to hook the spurious faults. */ + if (notify_page_fault(regs)) + return; /* * It's safe to allow irq's after cr2 has been saved and the