[PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault

[Peter Zijlstra]

With the removal of kprobe::handle_fault there is no reason left that
kprobe_page_fault() would ever return true on x86, make sure it
doesn't happen by accident.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/x86/mm/fault.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1186,7 +1186,7 @@ do_kern_addr_fault(struct pt_regs *regs,
 		return;
 
 	/* kprobes don't want to hook the spurious faults: */
-	if (kprobe_page_fault(regs, X86_TRAP_PF))
+	if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF)))
 		return;
 
 	/*
@@ -1239,7 +1239,7 @@ void do_user_addr_fault(struct pt_regs *
 	}
 
 	/* kprobes don't want to hook the spurious faults: */
-	if (unlikely(kprobe_page_fault(regs, X86_TRAP_PF)))
+	if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF)))
 		return;
 
 	/*