On the latest kernel/devel tree. $ cat git-branches.mk GIT_DIR = /home/caiqian/linux-2.6-utrace/.git head-utrace = utrace-ptrace branch-utrace-ptrace = utrace branch-utrace = tracehook $ make git/utrace/prep <it hung here witout any output> Checkout 2009-11-01 works fine. $ make git/utrace/prep make[1]: Entering directory `/home/caiqian/kernel/devel' ./gen-patches < kernel.spec > kernel.t.utrace.spec --name utrace v2.6.31 v2.6.32-rc5-git3 refs/remotes/upstream/master tracehook utrace utrace-ptrace make[2]: Entering directory `/home/caiqian/kernel/devel' Downloading linux-2.6.31.tar.bz2... Thanks, CAI Qian