Re: VMWare crashes

[Gary White]

Thanks,

I will apply the patch and see if it cures my problem.

Petr Vandrovec wrote:
> 
> On Mon, Jul 09, 2001 at 02:08:35PM -0500, Gary White (Network Administrator) wrote:
> > Here are the results of ksymoops...
> >
> > Code;  e1af85e1 <[vmnet]VNetHubCycleDetect+69/7c>   <=====
> >    0:   8b 42 70                  mov    0x70(%edx),%eax   <=====
> 
> Thanks, meanwhile I found simillar report on VMware newsgroups, so there must be
> something really real (it was with example how to reproduce it, so I received
> fine oops too).
> 
> Following patch fixes oopses, at least for me. Due to some changes in tasklets
> and/or in networking there is now very large quantum of skbs in flight from
> one part of vmnet (packet written to /dev/vmnet*) through netif_rx to another
> (packet received on eth0 interface). This trigerred 'history buffer overflow'
> message, which then started cleaning history buffer. And if two CPUs started
> cleaning at the same moment, one of them did kfree_skb(NULL) sooner or later...
> 
> So only increasing VNET_BRIDGE_HISTORY from 8 to 48 fixes problem, but as
> I do not want oopses, rest of this patch just fixes oopses themselves. If
> you'll apply patch except VNET_BRIDGE_HISTORY line, it will work, but you'll
> get large stream of 'history buffer full' messages when doing TCP transfers
> between guest and host. (48 is apparently enough for dual PIII/800, I did
> not tested lower values (48 is next multiple of 8 which ends on 8,
> this saved one keystroke and so on...))
> 
> For those unfamiliar with patch (I'm sure there are no on linux-kernel,
> but there can be some in VMware newsgroups) I put updated vmnet.tar.gz
> at ftp://platan.vc.cvut.cz/pub/vmware/vmnet-204-for-2.4.6.tar.gz
> 
>                                         Best regards,
>                                                 Petr Vandrovec
>                                                 [e-mail]
> 
> diff -urN vmnet-only.orig/bridge.c vmnet-only/bridge.c
> --- vmnet-only.orig/bridge.c    Thu Apr 26 19:59:28 2001
> +++ vmnet-only/bridge.c Mon Jul  9 21:50:36 2001
> @@ -44,7 +44,7 @@
>  #include "vnetInt.h"
> 
> 
> -#define VNET_BRIDGE_HISTORY    8
> +#define VNET_BRIDGE_HISTORY    48
> 
>  typedef struct VNetBridge VNetBridge;
> 
> @@ -58,6 +58,7 @@
>     Bool                     savedPromisc;
>     struct sk_buff          *history[VNET_BRIDGE_HISTORY];
>     VNetPort                 port;
> +   spinlock_t              historyLock;
>  };
> 
> 
> @@ -130,6 +131,7 @@
>        goto out;
>     }
>     memset(bridge, 0, sizeof *bridge);
> +   spin_lock_init(&bridge->historyLock);
>     memcpy(bridge->name, devName, sizeof bridge->name);
> 
>     /*
> @@ -391,6 +393,8 @@
>          unsigned long flags;
>          int i;
>          SKB_INCREF(clone);
> +
> +        spin_lock_irqsave(&bridge->historyLock, flags);
>          // XXX need to lock history
>          for (i = 0; i < VNET_BRIDGE_HISTORY; i++) {
>             if (bridge->history[i] == NULL) {
> @@ -417,11 +421,15 @@
>             for (i = 0; i < VNET_BRIDGE_HISTORY; i++) {
>                struct sk_buff *s = bridge->history[i];
>                bridge->history[i] = NULL;
> -              KFREE_SKB(s, FREE_WRITE);
> +              if (s) {
> +                 spin_unlock_irqrestore(&bridge->historyLock, flags);
> +                 KFREE_SKB(s, FREE_WRITE);
> +                 spin_lock_irqsave(&bridge->historyLock, flags);
> +              }
>             }
>             bridge->history[0] = clone;
>          }
> -
> +         spin_unlock_irqrestore(&bridge->historyLock, flags);
>          clone->dev = dev;
>          clone->protocol = eth_type_trans(clone, dev);
>          save_flags(flags);
> @@ -773,6 +781,7 @@
>  {
>     VNetBridge *bridge = *(VNetBridge**)&((struct sock *)pt->data)->protinfo;
>     int i;
> +   unsigned long flags;
> 
>     if (bridge->dev == NULL) {
>        LOG(3, (KERN_DEBUG "bridge-%s: received %d closed\n",
> @@ -782,11 +791,13 @@
>     }
> 
>     // XXX need to lock history
> +   spin_lock_irqsave(&bridge->historyLock, flags);
>     for (i = 0; i < VNET_BRIDGE_HISTORY; i++) {
>        struct sk_buff *s = bridge->history[i];
>        if (s != NULL &&
>           (s == skb || SKB_IS_CLONE_OF(skb, s))) {
>          bridge->history[i] = NULL;
> +        spin_unlock_irqrestore(&bridge->historyLock, flags);
>          KFREE_SKB(s, FREE_WRITE);
>          LOG(3, (KERN_DEBUG "bridge-%s: receive %d self %d\n",
>                  bridge->name, (int) skb->len, i));
> @@ -795,6 +806,7 @@
>          return 0;
>        }
>     }
> +   spin_unlock_irqrestore(&bridge->historyLock, flags);
> 
>  #  if LOGLEVEL >= 4
>     {

-- 
Gary White               Network Administrator
[e-mail]          Internet Pathway
Voice 601-776-3355            Fax [phone]