From 44bd887ce10eb8061f6a137f8a73f823957edd82 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 19 Jul 2016 15:07:39 +0100 Subject: [PATCH] arm64: kprobes: WARN if attempting to step with PSTATE.D=1 Stepping with PSTATE.D=1 is bad news. The step won't generate a debug exception and we'll likely walk off into random data structures. This should never happen, but when it does, it's a PITA to debug. Add a WARN_ON to shout if we realise this is about to take place. Signed-off-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/kernel/probes/kprobes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 9c70e8812ea9..c89811d1e294 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -254,6 +254,8 @@ static void __kprobes setup_singlestep(struct kprobe *p, if (kcb->kprobe_status == KPROBE_REENTER) spsr_set_debug_flag(regs, 0); + else + WARN_ON(regs->pstate & PSR_D_BIT); /* IRQs and single stepping do not mix well. */ kprobes_save_local_irqflag(kcb, regs); -- 2.20.1