From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765120AbXGYVyM (ORCPT ); Wed, 25 Jul 2007 17:54:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757346AbXGYVx5 (ORCPT ); Wed, 25 Jul 2007 17:53:57 -0400 Received: from mtiwmhc13.worldnet.att.net ([204.127.131.117]:56275 "EHLO mtiwmhc13.worldnet.att.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754277AbXGYVx4 (ORCPT ); Wed, 25 Jul 2007 17:53:56 -0400 Message-ID: <46A7C66E.305@lwfinger.net> Date: Wed, 25 Jul 2007 16:53:50 -0500 From: Larry Finger User-Agent: Thunderbird 1.5.0.12 (X11/20070509) MIME-Version: 1.0 To: LKML , luming.yu@intel.com, len.brown@intel.com, linux-acpi@vger.kernel.org Subject: Regression in 2.6.22-rc3 and newer - Kernel oops in acpi_processor_throttling-seq-show Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On an x86_64 system with an AMD Turion 64 X2 processor, I get the following kernel oops with any system later than 2.6.22-rc2: Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP: [] :processor:acpi_processor_throttling_seq_show+0x106/0x134 PGD 5ab65067 PUD 557d7067 PMD 0 Oops: 0000 [1] SMP CPU 0 Modules linked in: snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device vboxdrv cpufreq_conservative cpufreq_ondemand cpufreq_userspace cpufreq_powersave powernow_k8 freq_table button battery ac loop dm_mod nfsd exportfs lockd nfs_acl auth_rpcgss sunrpc snd_hda_intel snd_pcm sdhci ide_cd mmc_core ohci1394 snd_timer ieee1394 snd cdrom ohci_hcd ehci_hcd soundcore snd_page_alloc forcedeth i2c_nforce2 usbcore bcm43xx firmware_class ieee80211softmac ieee80211 ieee80211_crypt ext3 mbcache jbd edd sg fan sata_nv libata amd74xx thermal processor sd_mod scsi_mod ide_disk ide_core Pid: 3493, comm: powersaved Not tainted 2.6.23-rc1-Linus-g72f0027e-dirty #86 RIP: 0010:[] [] :processor:acpi_processor_throttling_seq_show+0x106/0x134 RSP: 0018:ffff810054687e28 EFLAGS: 00010246 RAX: 0000000000000020 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 000000000000002a RSI: ffffffff88061ab0 RDI: ffff81005a1f2948 RBP: ffff810054687e48 R08: 0000000000000002 R09: ffffffff80234979 R10: ffffffffffffffff R11: ffff8100539f0000 R12: ffff810037dc4848 R13: ffff81005a1f2948 R14: 0000000000000000 R15: 0000000000000000 FS: 00002adfd9159e50(0000) GS:ffffffff80522000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000037dce000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process powersaved (pid: 3493, threadinfo ffff810054686000, task ffff8100554acf60) Stack: ffff81005a1f2948 0000000000000001 0000000000000001 0000000000000400 ffff810054687eb8 ffffffff802aa52a ffff810054687e98 ffff810054687f48 00002adfd712c000 ffff8100531b5000 ffff81005a1f2978 ffffffff802aa41d Call Trace: [] seq_read+0x10d/0x29f [] seq_read+0x0/0x29f [] seq_read+0x0/0x29f [] proc_reg_read+0x8a/0xa7 [] vfs_read+0xab/0x134 [] sys_read+0x47/0x6f [] system_call+0x7e/0x83 Code: 45 8b 04 0e 89 d9 0f 45 d0 31 c0 48 ff c3 49 83 c6 28 e8 6b RIP [] :processor:acpi_processor_throttling_seq_show+0x106/0x134 RSP CR2: 0000000000000000 ============================================================== Using bisect, I localized the problem to the following commit: commit 01854e697a77a434104b2f7e6d7fd463a978af32 Author: Luming Yu Date: Sat May 26 22:49:58 2007 +0800 ACPI: add ACPI 3.0 _TPC _TSS _PTC throttling support adds _TPC _TSS _PTC -- Throttling Present Capabilities Signed-off-by: Luming Yu Signed-off-by: Len Brown The problem is that "acpi_processor_get_throttling_info" is never called for my cpu, which means that "acpi_processor_get_throttling_states" is never called, and no space is allocated for pr->throttling.states_tss. I didn't track the reason for not calling these routines, but leave that for the ACPI wizards. The following hack works for my system: ==================================================== Avoid a NULL pointer kernel oops on x86_64 caused by throttling.states_fss not being allocated. Signed-off-by: Larry Finger --- Index: linux-2.6/drivers/acpi/processor_throttling.c =================================================================== --- linux-2.6.orig/drivers/acpi/processor_throttling.c +++ linux-2.6/drivers/acpi/processor_throttling.c @@ -658,6 +658,12 @@ static int acpi_processor_throttling_seq pr->throttling.state_count - 1); seq_puts(seq, "states:\n"); + if ((acpi_processor_get_throttling != acpi_processor_get_throttling_fadt) + && !pr->throttling.states_tss) { + seq_puts(seq, + "There was no initialization of states_tss.\n"); + goto end; + } if (acpi_processor_get_throttling == acpi_processor_get_throttling_fadt) for (i = 0; i < pr->throttling.state_count; i++) seq_printf(seq, " %cT%d: %02d%%\n",