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Revision 95ef1e52922cf75b1ea2eae54ef886f2cc47eecb authored by Avi Kivity on 15 November 2011, 12:59:07 UTC, committed by Avi Kivity on 20 November 2011, 08:53:48 UTC 
KVM guest: prevent tracing recursion with kvmclock
 
Prevent tracing of preempt_disable() in get_cpu_var() in
kvm_clock_read(). When CONFIG_DEBUG_PREEMPT is enabled,
preempt_disable/enable() are traced and this causes the function_graph
tracer to go into an infinite recursion. By open coding the
preempt_disable() around the get_cpu_var(), we can use the notrace
version which prevents preempt_disable/enable() from being traced and
prevents the recursion.

Based on a similar patch for Xen from Jeremy Fitzhardinge.

Tested-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
1 parent bb75c62
Raw File
crc.h 
/*********************************************************************
 *                
 * Filename:      crc.h
 * Version:       
 * Description:   CRC routines
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Mon Aug  4 20:40:53 1997
 * Modified at:   Sun May  2 20:25:23 1999
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 * 
 ********************************************************************/

#ifndef IRDA_CRC_H
#define IRDA_CRC_H

#include <linux/types.h>
#include <linux/crc-ccitt.h>

#define INIT_FCS  0xffff   /* Initial FCS value */
#define GOOD_FCS  0xf0b8   /* Good final FCS value */

/* Recompute the FCS with one more character appended. */
#define irda_fcs(fcs, c) crc_ccitt_byte(fcs, c)

/* Recompute the FCS with len bytes appended. */
#define irda_calc_crc16(fcs, buf, len) crc_ccitt(fcs, buf, len)

#endif
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