From: Balbir Singh <bsinghar...@gmail.com>

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 <pau...@samba.org>
Signed-off-by: Balbir Singh <bsinghar...@gmail.com>
---
 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

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