While trying to get http://darcs.haskell.org/ghc-stable/packages/pretty
by invoking `darcs get --partial
http://darcs.haskell.org/ghc-stable/packages/pretty' command as part of
GHC buildprocess on GHC buildbot I've notices that this darcs never
finishes its `Identifying repository
http://darcs.haskell.org/ghc-stable/packages/pretty
' step. It seems there is some live-lock involved while calling licurl
functions. This is on Solaris 11, ghc 6.8.2.20080430, darcs from May 22,
linked against curl 7.18.0 with curl pipelining enabled.

As this is on Solaris I've saved few process's stacktraces by using
pstack(1) command. It seems darcs is again and again invoking following
trace:

-----------------  lwp# 1 / thread# 1  --------------------
 fea545b7 gettimeofday (80459c0, 8561e60, 80459d8, feed829d, 80459c0,
8561e64) + 7
 feed82da curl_multi_perform (8561e60, 8045a2c, 0, 0, 0, 0) + 8e
 0841e5db curl_wait_next_url (0, 0, 0, 0, 0, 0) + 37
 08189e3d ???????? (fe3ec8c1, fe3ec8ce, fe3ec8e7, fe3ec8f0, 818b29c,
fe3ec8fa)
 00000001 ???????? (c5830818, a79ae9fc, f689002e, 384ab0, 4, ffff0022)
 b11c0045 ???????? ()

Anyway whole log saved by few seconds running `while (true) do pstack
<darcs pid>; done is attached.

Could anybody be so kind and try to duplicate this issue on Linux? Also
if anybody is able to tell me how to get rid of question marks in the
trace and replace them with appropriate GHC generated functions name,
then I would be glad to provide "fixed" stacktrace to show more
information about the issue. Thanks!

PS: Please note this is in Solaris running on real-metal, not in broken
VirtualBox!

Attachments

• darcs_live_lock_stacks.txt.gz