From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Mon, 30 Oct 2017 17:42:52 +0000 (+0000)
Subject: common/spinlock: Improve the output from check_lock() if it trips
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~1045^2~1
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=a79d4503e48739b48533737de6978397d8b3e69e;p=xen.git

common/spinlock: Improve the output from check_lock() if it trips

If check_lock() triggers, a crash will occur.  Instead of simply identifying
"the irq context was different", indicate the expected and current irq
context.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Release-acked-by: Julien Grall <julien.grall@linaro.org>
---

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 44b07b7f1c..8f2ba0818c 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -44,7 +44,13 @@ static void check_lock(struct lock_debug *debug)
     if ( unlikely(debug->irq_safe != irq_safe) )
     {
         int seen = cmpxchg(&debug->irq_safe, -1, irq_safe);
-        BUG_ON(seen == !irq_safe);
+
+        if ( seen == !irq_safe )
+        {
+            printk("CHECKLOCK FAILURE: prev irqsafe: %d, curr irqsafe %d\n",
+                   seen, irq_safe);
+            BUG();
+        }
     }
 }