Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763879AbXJQKxp (ORCPT ); Wed, 17 Oct 2007 06:53:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757703AbXJQKxh (ORCPT ); Wed, 17 Oct 2007 06:53:37 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:54875 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753687AbXJQKxg (ORCPT ); Wed, 17 Oct 2007 06:53:36 -0400 Date: Wed, 17 Oct 2007 03:53:27 -0700 From: Paul Jackson To: ego@in.ibm.com Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, vatsa@in.ibm.com, rusty@rustcorp.com.au, dipankar@in.ibm.com, oleg@tv-sign.ru, mingo@elte.hu, paulmck@us.ibm.com Subject: Re: [RFC PATCH 1/4] Refcount Based Cpu-Hotplug Implementation Message-Id: <20071017035327.ff1ed622.pj@sgi.com> In-Reply-To: <20071016103417.GA16570@in.ibm.com> References: <20071016103308.GA9907@in.ibm.com> <20071016103417.GA16570@in.ibm.com> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3873 Lines: 81 This patch dies on boot for me, using sn2_defconfig. It is dies on the kernel/cpu.c line: mutex_lock(&cpu_hotplug.lock); This is in cpu_hotplug_begin(), called from _cpu_up(), called from cpu_up(). I haven't finished verifying this yet, but it looks like the initialization of the mutex cpu_hotplug.lock in cpu_hotplug_init() only happens if CONFIG_HOTPLUG_CPU is enabled, but the use of that mutex in the above mutex_lock() call happens on all configs. In the sn2_defconfig I'm using, as well as in several other ia64, mips and powerpc configs, CONFIG_HOTPLUG_CPU is, at present anyway, disabled. For the record, the kernel death messages are: === Unable to handle kernel NULL pointer dereference (address 0000000000000000) swapper[1]: Oops 8804682956800 [1] Modules linked in: Pid: 1, CPU 0, comm: swapper psr : 00001010085a2010 ifs : 800000000000038b ip : [] Not tainted ip is at __mutex_lock_slowpath+0x280/0x660 unat: 0000000000000000 pfs : 000000000000038b rsc : 0000000000000003 rnat: 1fcc5c7d8b12a4b4 bsps: 000000000001003e pr : 0000000000001041 ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70433f csd : 0000000000000000 ssd : 0000000000000000 b0 : a00000010081e040 b6 : e0000030025bee60 b7 : a0000001005315c0 f6 : 1003e1111111111111111 f7 : 1003e20c49ba5e353f7cf f8 : 1003e00000000000000c8 f9 : 10006c7fffffffd73ea5c f10 : 100019ffffffff8a77fd5 f11 : 1003e0000000000000000 r1 : a000000101064760 r2 : a00000010118ef80 r3 : e00000b020377b20 r8 : e00000b020377d00 r9 : 0000000000004000 r10 : e00000b020370b58 r11 : e00000b020370000 r12 : e00000b020377cf0 r13 : e00000b020370000 r14 : 0000000000000001 r15 : e00000b020377d18 r16 : e00000b020377768 r17 : 00000000dead4ead r18 : a000000100d01380 r19 : a000000100e68300 r20 : 0000000000004000 r21 : 0000000000000010 r22 : 0000000000000000 r23 : 0000000000000000 r24 : 0000000000004000 r25 : ffffffffffffffff r26 : e00000b020377d10 r27 : 0000000000000000 r28 : e00000b020377d00 r29 : e00000b020377d08 r30 : a00000010118efa0 r31 : a00000010118ef98 Call Trace: [] show_stack+0x40/0xa0 sp=e00000b0203778c0 bsp=e00000b020370f80 [] show_regs+0x840/0x880 sp=e00000b020377a90 bsp=e00000b020370f28 [] die+0x220/0x300 sp=e00000b020377a90 bsp=e00000b020370ee0 [] ia64_do_page_fault+0x910/0xa80 sp=e00000b020377a90 bsp=e00000b020370e90 [] ia64_leave_kernel+0x0/0x280 sp=e00000b020377b20 bsp=e00000b020370e90 [] __mutex_lock_slowpath+0x280/0x660 sp=e00000b020377cf0 bsp=e00000b020370e38 [] mutex_lock+0x40/0x60 sp=e00000b020377d20 bsp=e00000b020370e18 [] cpu_up+0x220/0x6a0 sp=e00000b020377d20 bsp=e00000b020370dd0 [] kernel_init+0x250/0x7e0 sp=e00000b020377d30 bsp=e00000b020370d88 [] kernel_thread_helper+0xd0/0x100 sp=e00000b020377e30 bsp=e00000b020370d60 [] start_kernel_thread+0x20/0x40 sp=e00000b020377e30 bsp=e00000b020370d60 Kernel panic - not syncing: Attempted to kill init! -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/