*** printk.c~	Fri Jun 30 16:24:38 2000
--- printk.c	Sat Jul  1 11:18:41 2000
***************
*** 19,32 ****
  #include <linux/smp_lock.h>
  #include <linux/console.h>
  #include <linux/init.h>
  
  #include <asm/uaccess.h>
  
  #define LOG_BUF_LEN	(16384)
  #define LOG_BUF_MASK	(LOG_BUF_LEN-1)
  
- static char buf[1024];
- 
  /* printk's without a loglevel use this.. */
  #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
  
--- 19,31 ----
  #include <linux/smp_lock.h>
  #include <linux/console.h>
  #include <linux/init.h>
+ #include <linux/slab.h>
  
  #include <asm/uaccess.h>
  
  #define LOG_BUF_LEN	(16384)
  #define LOG_BUF_MASK	(LOG_BUF_LEN-1)
  
  /* printk's without a loglevel use this.. */
  #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
  
***************
*** 253,271 ****
  
  asmlinkage int printk(const char *fmt, ...)
  {
  	va_list args;
  	int i;
  	char *msg, *p, *buf_end;
  	int line_feed;
  	static signed char msg_level = -1;
  	long flags;
  
  	va_start(args, fmt);
  	i = vsprintf(buf + 3, fmt, args); /* hopefully i < sizeof(buf)-4 */
  	buf_end = buf + 3 + i;
  	va_end(args);
! 	
  	spin_lock_irqsave(&console_lock, flags);
  	for (p = buf + 3; p < buf_end; p++) {
  		msg = p;
  		if (msg_level < 0) {
--- 252,292 ----
  
  asmlinkage int printk(const char *fmt, ...)
  {
+ 	static spinlock_t printk_buf_lock = SPIN_LOCK_UNLOCKED;
+ 	static struct task_struct *printk_buf_holder = 0;
+ 	static char printk_buf[1024];
+ 
  	va_list args;
  	int i;
  	char *msg, *p, *buf_end;
  	int line_feed;
  	static signed char msg_level = -1;
  	long flags;
+ 	char *buf = printk_buf;
+ 
+ 	if (!spin_trylock(&printk_buf_lock)) {
+ 		/* Couldn't get spinlock... do we already have it? */
+ 		if (printk_buf_holder == current) {
+ 			/* Yup, don't clobber printk_buf, use a temporary one 
+ 			 * instead... this is a very uncommon case...
+ 			 */
+ 			buf = (char*)kmalloc(1024, GFP_KERNEL);
+ 		} else {
+ 			/* Nope, wait for someone to release it... */
+ 			spin_lock(&printk_buf_lock);
+        		}
+ 	}
+ 
+ 	/* We are now the proud holders of the printk_buf_lock! :) */
+ 	printk_buf_holder = current;
  
  	va_start(args, fmt);
  	i = vsprintf(buf + 3, fmt, args); /* hopefully i < sizeof(buf)-4 */
  	buf_end = buf + 3 + i;
  	va_end(args);
! 
  	spin_lock_irqsave(&console_lock, flags);
+ 	
  	for (p = buf + 3; p < buf_end; p++) {
  		msg = p;
  		if (msg_level < 0) {
***************
*** 308,315 ****
--- 329,346 ----
  		if (line_feed)
  			msg_level = -1;
  	}
+ 
  	spin_unlock_irqrestore(&console_lock, flags);
  	wake_up_interruptible(&log_wait);
+ 
+ 	if (buf != printk_buf) {
+ 		/* We recursed into printk... release our temporary buffer.. */
+ 		kfree(buf);
+        	} else {
+ 		/* This is the normal case... just release the spinlock... */
+ 		spin_unlock(&printk_buf_lock);
+ 	}
+         
  	return i;
  }