Still something wrong with tcp_sack_option ()

[Mohan Srinivasan]

Hi,

Noritoshi Demizu sent me a fix for this issue. Can you try 
this fix ? I'll get this committed to -current shortly.

It looks like because you run with larger windows, generating
a lot of sack holes, we ran into the sackhole limits that
caused allocation of a new sackhole to fail, causing the bug.

thanks !

mohan

Index: tcp_sack.c
===================================================================
RCS file: /home/cvsup/FreeBSD/ncvs/src/sys/netinet/tcp_sack.c,v
retrieving revision 1.22
diff -u -r1.22 tcp_sack.c
--- tcp_sack.c  6 Jun 2005 19:46:53 -0000       1.22
+++ tcp_sack.c  8 Jun 2005 03:18:42 -0000
@@ -458,13 +458,19 @@
                 * beyond the current fack, they will be inserted by
                 * way of hole splitting in the while-loop below.
                 */
-               tcp_sackhole_insert(tp, tp->snd_fack, sblkp->start, NULL);
+               temp = tcp_sackhole_insert(tp, tp->snd_fack,sblkp->start,NULL);
+               if (temp == NULL)
+                       return 0;
                tp->snd_fack = sblkp->end;
                /* Go to the previous sack block. */
                sblkp--;
        } else if (SEQ_LT(tp->snd_fack, sblkp->end))
                /* fack is advanced. */
                tp->snd_fack = sblkp->end;
+       /*
+        * At this point, at least one SACK hole must exist.
+        */
+       KASSERT(!TAILQ_EMPTY(&tp->snd_holes), ("SACK scoreboard is emtpy"));
        cur = TAILQ_LAST(&tp->snd_holes, sackhole_head); /* Last SACK hole */
        /*
         * Since the incoming sack blocks are sorted, we can process them

--- Andrey Chernov <ache at nagual.pp.ru> wrote:
> On Tue, Jun 07, 2005 at 07:01:22PM -0700, Mohan Srinivasan wrote:
> > Yes. That will work around it too.
> > 
> 
> I forget to mention that I use relatively large send/recvspace, about 
> 128K, it may increase bug trigger because SACK happens often.
> 
> -- 
> http://ache.pp.ru/
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