Re: [uml-devel] Patchset to implement PTRACE_SYSEMU_SINGLESTEP

[Bodo Stroesser <bstroesser@fujitsu-siemens.com>]

Jeff Dike wrote:
> bstroesser@fujitsu-siemens.com said:
> 
>>What happens on my system shows some other symptoms. After "Restarting
>>system." UML exits without further message. I could track this down to
>>a SIGIO being unblocked immediately before the execvp(). It is handled
>>by sig_handler() that calls sig_handler_common_skas(). Why this exits,
>>I don't know. 
> 
> 
> Try this patch.  It adds the missing closes that you found today, plus it
> makes sure that netdevices get closed down correctly.
> 
> 				Jeff

Yes. I've tested and mostly it works fine. Only one litte change is needed
to have the daemon-network working after "network stop" and "network start".
I commented it in the patch.

         Bodo

> 
> Index: 2.6.9/arch/um/drivers/net_kern.c
> ===================================================================
> --- 2.6.9.orig/arch/um/drivers/net_kern.c	2004-11-17 22:25:19.000000000 -0500
> +++ 2.6.9/arch/um/drivers/net_kern.c	2004-11-17 23:18:21.000000000 -0500
> @@ -126,10 +126,6 @@
>  	lp->tl.data = (unsigned long) &lp->user;
>  	netif_start_queue(dev);
>  
> -	spin_lock(&opened_lock);
> -	list_add(&lp->list, &opened);
> -	spin_unlock(&opened_lock);
> -
>  	/* clear buffer - it can happen that the host side of the interface
>  	 * is full when we get here.  In this case, new data is never queued,
>  	 * SIGIOs never arrive, and the net never works.
> @@ -150,11 +146,10 @@
>  
>  	free_irq_by_irq_and_dev(dev->irq, dev);
A little question: what about the "free_irq_by_irq_and_dev"? In my sources they
are missing, and I couldn't find a patch relating this. My daemon works without it.
>  	free_irq(dev->irq, dev);


> -	if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
> -	lp->fd = -1;
These two lines should be unchanged. lp->fd must be set to -1, since net_kern
for all networks takes this as a "is-closed" flag and refuses to open,
if lp->fd != -1. Daemon stores its fds in a private struct and returns it in
case of an open(). Thus, lp->fd is set to daemon's fd on each open().


> -	spin_lock(&opened_lock);
> -	list_del(&lp->list);
> -	spin_unlock(&opened_lock);
Yes. This must be removed.


> +	if(lp->close != NULL){
> +		(*lp->close)(lp->fd, &lp->user);
> +		lp->fd = -1;
> +	}
No. This must not be inserted.


>  
>  	spin_unlock(&lp->lock);
>  	return 0;
> @@ -289,7 +284,7 @@
>  static spinlock_t devices_lock = SPIN_LOCK_UNLOCKED;
>  static struct list_head devices = LIST_HEAD_INIT(devices);
>  
> -static int eth_configure(int n, void *init, char *mac,
> +static int eth_configure(int n, void *init, char *mac, 
>  			 struct transport *transport)
>  {
>  	struct uml_net *device;
> @@ -397,6 +392,11 @@
>  
>  	if (device->have_mac)
>  		set_ether_mac(dev, device->mac);
> +
> +	spin_lock(&opened_lock);
> +	list_add(&lp->list, &opened);
> +	spin_unlock(&opened_lock);
> +
>  	return(0);
>  }
>  
> @@ -705,7 +705,7 @@
>  static void close_devices(void)
>  {
>  	struct list_head *ele;
> -	struct uml_net_private *lp;	
> +	struct uml_net_private *lp;
>  
>  	list_for_each(ele, &opened){
>  		lp = list_entry(ele, struct uml_net_private, list);
> Index: 2.6.9/arch/um/kernel/initrd_user.c
> ===================================================================
> --- 2.6.9.orig/arch/um/kernel/initrd_user.c	2004-11-17 22:25:19.000000000 -0500
> +++ 2.6.9/arch/um/kernel/initrd_user.c	2004-11-17 22:26:24.000000000 -0500
> @@ -29,6 +29,8 @@
>  		       filename, -n);
>  		return(-1);
>  	}
> +
> +	os_close_file(fd);
>  	return(0);
>  }
>  
> Index: 2.6.9/arch/um/kernel/mem_user.c
> ===================================================================
> --- 2.6.9.orig/arch/um/kernel/mem_user.c	2004-11-17 22:25:19.000000000 -0500
> +++ 2.6.9/arch/um/kernel/mem_user.c	2004-11-17 22:26:24.000000000 -0500
> @@ -101,6 +101,8 @@
>  	}
>  	printf("OK\n");
>  	munmap(addr, UM_KERN_PAGE_SIZE);
> +
> +	os_close_file(fd);
>  }
>  
>  static int have_devanon = 0;
> 



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