Using CONFIG_PREEMPT_RCU and CONFIG_NO_IDLE_HZ on s390 my system always gets stuck when running with more than one cpu. When booting with four cpus I get all four cpus caught withing cpu_idle and not advancing anymore. However there is the init process which is waitung for synchronize_rcu() to complete (lcrash output):
STACK TRACE FOR TASK: 0xf84d968 (swapper) STACK: 0 schedule+842 [0x36c956] 1 schedule_timeout+172 [0x36d0e4] 2 wait_for_common+204 [0x36c398] 3 synchronize_rcu+76 [0x567bc] 4 netlink_change_ngroups+150 [0x2b4302] 5 genl_register_mc_group+256 [0x2b6174] 6 genl_init+188 [0x534e44] 7 kernel_init+444 [0x518334] 8 kernel_thread_starter+6 [0x192a6] If I change the code so that timer ticks won't be disabled everything runs fine. So my guess is that rcu_needs_cpu() doesn't do the right thing for the rcu preemptible case. Kernel version is git head of today. Any ideas? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
