From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x230.google.com (mail-pf0-x230.google.com [IPv6:2607:f8b0:400e:c00::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id D247D1A358C for ; Wed, 17 Feb 2016 15:43:18 +1100 (AEDT) Received: by mail-pf0-x230.google.com with SMTP id q63so4286449pfb.0 for ; Tue, 16 Feb 2016 20:43:18 -0800 (PST) Message-ID: <1455684191.3089.3.camel@gmail.com> Subject: Fix BUG_ON() reporting in real mode on powerpc From: Balbir Singh To: Michael Ellerman , linuxppc-dev@lists.ozlabs.org Cc: Paul Mackerras Date: Wed, 17 Feb 2016 15:43:11 +1100 Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Balbir Singh I ran into this issue while debugging an early boot problem. The system hit a BUG_ON() but report bug failed to print the line number and file name. The reason being that the system was running in real mode and report_bug() searches for addresses in the PAGE_OFFSET+ region Suggested-by: Paul Mackerras Signed-off-by: Balbir Singh ---  arch/powerpc/kernel/traps.c | 8 +++++++-  1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index b6becc7..8f28120 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1148,6 +1148,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)   goto bail;   }   if (reason & REASON_TRAP) { + unsigned long bugaddr;   /* Debugger is first in line to stop recursive faults in    * rcu_lock, notify_die, or atomic_notifier_call_chain */   if (debugger_bpt(regs)) @@ -1158,8 +1159,13 @@ void __kprobes program_check_exception(struct pt_regs *regs)   == NOTIFY_STOP)   goto bail;   + if (!(regs->msr & MSR_IR)) + bugaddr = regs->nip + PAGE_OFFSET; + else + bugaddr = regs->nip; +   if (!(regs->msr & MSR_PR) &&  /* not user-mode */ -     report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { +     report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {   regs->nip += 4;   goto bail;   } --  2.5.0