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 <mhiramat@redhat.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 90dfae5..c76ef1d 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -603,8 +603,6 @@
si_code = SEGV_MAPERR;
- if (notify_page_fault(regs))
- return;
if (unlikely(kmmio_fault(regs, address)))
return;
@@ -634,6 +632,9 @@
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 @@
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