From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kimio Suganuma Date: Thu, 08 Aug 2002 04:19:20 +0000 Subject: Re: [Linux-ia64] Re: CPU hotplug boot change for IA64 Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hi, On Tue, 6 Aug 2002 20:33:09 +0200 Erich Focht wrote: > The patch looks fine. Before applying it to 2.5.29 my BigSur ended up > with no tasks beeing scheduled to cpu#1 and no migration_task and > ksoftirqd for the same cpu. > > But the system came up. After applying it > the system hangs in the boot sequence right after "Freeing unused > kernel memory". But CPU#1 was woken up correctly. Sorry, have no kdb > to be able to tell you more... > > Does anybody else have these problems? ksoftirqd and migration_thread are spawned in cpu_up() in kernel/cpu.c. But, cpu_up() wasn't called because the cpu had already been running at that time (see arch/ia64/kernel/smpboot.c and init/main.c.) I tried to change init/main.c to call cpu_up() for APs, and I made sure that the kernel caused the system hangs as you reported. This means that 2.5.29 kernel is not stable on SMP regardless of CPU Hot Plug patch applying. I found that kudzu(1) and shutdown of ethernet may cause system hangs but I'm not sure why. Regards, Kimi -- Kimio Suganuma