sbflush_locked panic and tcp_sack

Andre Oppermann andre at
Mon Sep 19 05:23:38 PDT 2005

Maxim Konovalov wrote:
> Hi,
> I got a panic at the end of sbflush_locked() on recent -current when
> open a large photo gallery with firefox.
> if (sb->sb_cc || sb->sb_mb || sb->sb_mbcnt)
>                 panic("sbflush_locked: cc %u || mb %p || mbcnt %u", sb->sb_cc,
> 			(void *)sb->sb_mb, sb->sb_mbcnt);
> It seems I can reproduce this panic easily.  Moreover, turning
> tcp_sack off eliminates this panic.  Does anybody see that?

This rings a bell.  Sounds like a problem with delayed header drop in TCP
segments.  In tcp_input() have the variable "tlen" examined.


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