Subject: [PATCH 2/2] powerpc: fix second nested oops hang

From: Nicholas Piggin <[email-masked]>
Date: Tue, 8 Nov 2016 23:14:45 +1100

When ending an oops, don't clear die_owner unless the nest count
went to zero. This prevents a second nested oops from hanging forever
on the die_lock.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/traps.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 26c3ba4..ba78e38 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -147,14 +147,15 @@ static void oops_end(unsigned long flags, struct pt_regs *regs,
 			       int signr)
 {
 	bust_spinlocks(0);
-	die_owner = -1;
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	die_nest_count--;
 	oops_exit();
 	printk("\n");
-	if (!die_nest_count)
+	if (!die_nest_count) {
 		/* Nest count reaches zero, release the lock. */
+		die_owner = -1;
 		arch_spin_unlock(&die_lock);
+	}
 	raw_local_irq_restore(flags);
 
 	crash_fadump(regs, "die oops");
-- 
2.10.2