[Pkg-gnupg-maint] Bug#614963: gnupg: gpg freezes with a zombie child gpgkeys_hkp after a Ctrl-C

[NIIBE Yutaka]

merge 399904 614963
thanks

I can reproduce this bug 100% with the following procedure
on wheezy.

Prepare gnupg-1.4.12-7 environment by:

 apt-get source gnupg
 apt-get build-dep  gnupg
 cd gnupg-1.4.12
 debuild

Run gpg (gnupg-1.4.12/build-deb/g10/gdb) under gdb, by:

  (gdb) break mpi_alloc_limb_space
  (gdb) run --keyring /usr/share/keyrings/debian-keyring.gpg --list-key
  [ it stops at mpi_alloc_limb_space ]
  (gdb) cont
  [ again, it stops at mpi_alloc_limb_space ]
  (gdb) cont
  [ again, it stops at mpi_alloc_limb_space ]
  (gdb) cont
  [ again, it stops at mpi_alloc_limb_space ]
  (gdb) break malloc
  [ it stops at malloc ]
  (gdb) stepi
  [ ... ]
  (gdb) stepi <--- until it goes to...
  0x00007fb7c9a3d348

Then, 

  (gdb) info proc

and identify the PID of gpg.  Then, send signal by:

  $ kill -HUP <PID-OF-GPG>

Back to gdb:

  (gdb) cont

... and you will see it hangs.  Or you can setup:

  (gdb) catch syscall futex

to catch the futex call.

I sent my fix to #399904.  Since it is the bug in GnuPG, I reassigned
#399904 to gnupg.  Now, I merge this 614963 to 399904.
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