[squid-users] Frequent "assertion failed: forward.cc:500: "server_fd == fd"" errors

On all of my 4 squid servers I'm getting these assertion failures:

proxy-cbf-2:

NULL
{Accept: */*
Content-Type: application/x-www-form-urlencoded
2010/09/21 21:36:31| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 21:49:38| squidaio_queue_request: WARNING - Queue congestion
2010/09/21 22:13:49| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 22:15:00| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 22:16:08| sentRequestBody error: FD 194: (0) Success
2010/09/21 22:16:08| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 22:16:08| assertion failed: forward.cc:500: "server_fd == fd"

and proxy-cvk-1:

2010/09/21 21:13:45| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 21:17:39| squidaio_queue_request: WARNING - Queue congestion
2010/09/21 21:30:05| squidaio_queue_request: WARNING - Queue congestion
2010/09/21 21:50:46| squidaio_queue_request: WARNING - Queue congestion
2010/09/21 22:05:29| TunnelStateData::Connection::error: FD 465: read/write failure: (110) Connection timed out
2010/09/21 22:05:30| TunnelStateData::Connection::error: FD 377: read/write failure: (110) Connection timed out
2010/09/21 22:05:30| TunnelStateData::Connection::error: FD 455: read/write failure: (110) Connection timed out
2010/09/21 22:20:15| sentRequestBody error: FD 178: (0) Success
2010/09/21 22:20:15| statusIfComplete: Request not yet fully sent "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
2010/09/21 22:20:15| assertion failed: forward.cc:500: "server_fd == fd"

In both cases "POST http://setiboinc.ssl.berkeley.edu/sah_cgi/cgi"
seems to coincide with these failures.

I'm running yesterdays bzr HEAD:
2010/09/21 22:20:16| Starting Squid Cache version 3.HEAD-BZR for i686-pc-linux-gnu...

-- 
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt@charite.de | http://www.charite.de