From mboxrd@z Thu Jan  1 00:00:00 1970
From: Glauber de Oliveira Costa <gcosta@redhat.com>
Subject: [PATCH] BUG() on soft lockup upon suspend/resume
Date: Mon, 9 Oct 2006 18:22:42 -0300
Message-ID: <20061009212242.GB28540@redhat.com>
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Hi,

In systems with vcpu > 1, a BUG due to a detected soft lockup seems to be 
triggered after system resume/suspend. This is probably due to the lack of 
seqlocking around the region that does the local time processing. 

The following patch fix this.

-- 
Glauber de Oliveira Costa
Red Hat Inc.
"Free as in Freedom"

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--- linux-2.6.18-orig/arch/i386/kernel/time-xen.c	2006-10-06 14:37:41.000000000 -0400
+++ linux-2.6.18.x86_64/arch/i386/kernel/time-xen.c	2006-10-09 17:13:54.000000000 -0400
@@ -666,6 +666,13 @@ irqreturn_t timer_interrupt(int irq, voi
 		clock_was_set();
 	}
 
+	/* Local timer processing (see update_process_times()). */
+	run_local_timers();
+	if (rcu_pending(cpu))
+		rcu_check_callbacks(cpu, user_mode(regs));
+	scheduler_tick();
+	run_posix_cpu_timers(current); 
+
 	write_sequnlock(&xtime_lock);
 
 	/*
@@ -709,13 +716,6 @@ irqreturn_t timer_interrupt(int irq, voi
 					    (cputime_t)delta_cpu);
 	}
 
-	/* Local timer processing (see update_process_times()). */
-	run_local_timers();
-	if (rcu_pending(cpu))
-		rcu_check_callbacks(cpu, user_mode(regs));
-	scheduler_tick();
-	run_posix_cpu_timers(current);
-
 	return IRQ_HANDLED;
 }
 

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