FYI, we noticed the following commit: git://git.cmpxchg.org/linux-mmotm.git master commit 07f2c934205df0266ed8700cc173e5150eda2417 ("softirq: fix tasklet_kill() and its users") in testcase: boot on test machine: qemu-system-i386 -enable-kvm -m 360M caused below changes: +-------------------------------------------------+------------+------------+ | | 987cf1d527 | 07f2c93420 | +-------------------------------------------------+------------+------------+ | boot_successes | 15 | 4 | | boot_failures | 1 | 12 | | BUG:kernel_reboot-without-warning_in_test_stage | 1 | | | BUG:kernel_hang_in_test_stage | 0 | 12 | +-------------------------------------------------+------------+------------+ [ 377.026314] reboot: Restarting system Elapsed time: 1640 BUG: kernel hang in test stage initrds=( /osimage/quantal/quantal-core-i386.cgz Thanks, Kernel Test Robot