From: Keir Fraser <keir.fraser@citrix.com>
Date: Tue, 18 May 2010 12:30:45 +0000 (+0100)
Subject: x86-hpet: fix booting NULL pointer panic introduced by c/s 21398.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~12131
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks://%22/%22http:/www.example.com/cgi/%22https:/%22bookmarks:/%22?a=commitdiff_plain;h=ca3ab005c14186c4b319a0995f25a0cab1092835;p=xen.git

x86-hpet: fix booting NULL pointer panic introduced by c/s 21398.

(XEN) Xen call trace:
(XEN)    [<ffff82c48011fb27>] check_lock+0x19/0x49
(XEN)    [<ffff82c48011ff2a>] _spin_lock_irq+0x28/0x4a
(XEN)    [<ffff82c48018fd6d>] hpet_broadcast_exit+0x92/0x1f0
(XEN)    [<ffff82c4801920b2>] acpi_processor_idle+0x62c/0x6e6
(XEN)    [<ffff82c48014e1a1>] idle_loop+0x62/0x73

Signed-off-by: Wei Gang <gang.wei@intel.com>
---

diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c
index 556368632a..e67e5ce5d3 100644
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -684,6 +684,9 @@ void hpet_broadcast_exit(void)
     if ( this_cpu(timer_deadline_start) == 0 )
         return;
 
+    if ( !ch )
+        ch = hpet_get_channel(cpu);
+
     /* Reprogram the deadline; trigger timer work now if it has passed. */
     enable_APIC_timer();
     if ( !reprogram_timer(this_cpu(timer_deadline_start)) )