Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757380Ab3EUCVG (ORCPT ); Mon, 20 May 2013 22:21:06 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:56581 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732Ab3EUCVD (ORCPT ); Mon, 20 May 2013 22:21:03 -0400 Message-ID: <519ADA03.5060206@linux.vnet.ibm.com> Date: Tue, 21 May 2013 10:20:51 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Borislav Petkov CC: Viresh Kumar , Tejun Heo , "Paul E. McKenney" , Jiri Kosina , Frederic Weisbecker , Tony Luck , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , rjw@sisk.pl, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2 References: <20130520045023.GA12690@pd.tnic> <5199C169.7060504@linux.vnet.ibm.com> <20130520064727.GD12690@pd.tnic> <5199C990.3020602@linux.vnet.ibm.com> <5199CB59.1020309@linux.vnet.ibm.com> <5199CFD0.9030101@linux.vnet.ibm.com> <5199E54D.7030407@linux.vnet.ibm.com> <5199EBB5.7060209@linux.vnet.ibm.com> <20130520132355.GF12690@pd.tnic> In-Reply-To: <20130520132355.GF12690@pd.tnic> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13052102-5564-0000-0000-00000802C408 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 19257 Lines: 304 On 05/20/2013 09:23 PM, Borislav Petkov wrote: > On Mon, May 20, 2013 at 05:24:05PM +0800, Michael Wang wrote: >>>> diff --git a/drivers/cpufreq/cpufreq_governor.c >>>> b/drivers/cpufreq/cpufreq_governor.c >>>> index 443442d..449be88 100644 >>>> --- a/drivers/cpufreq/cpufreq_governor.c >>>> +++ b/drivers/cpufreq/cpufreq_governor.c >>>> @@ -26,6 +26,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> >>>> #include "cpufreq_governor.h" >>>> >>>> @@ -180,8 +181,10 @@ void gov_queue_work(struct dbs_data *dbs_data, >>>> struct cpufreq_policy *policy, >>>> if (!all_cpus) { >>>> __gov_queue_work(smp_processor_id(), dbs_data, delay); >>>> } else { >>>> + get_online_cpus(); >>>> for_each_cpu(i, policy->cpus) >>>> __gov_queue_work(i, dbs_data, delay); >>>> + put_online_cpus(); >>>> } >>>> } >>>> EXPORT_SYMBOL_GPL(gov_queue_work); >>>> >>>> This is supposed to make WARN disappear, if it works, then BINGO :) >>> >>> Let people test it and then we can talk :) >> >> Agree :) >> >> Borislav, would you like to take a try? >> >> If this fix cause other troubles, you could try get_cpu() or disable irq >> also. > > I just confirmed that policy->cpus contains offlined cores with this: > > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c > index 5af40ad82d23..e8c25f71e9b6 100644 > --- a/drivers/cpufreq/cpufreq_governor.c > +++ b/drivers/cpufreq/cpufreq_governor.c > @@ -169,6 +169,9 @@ static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data, > { > struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); > > + if (WARN_ON(!cpu_online(cpu))) > + return; > + This is not enough to prove that policy->cpus is wrong, the cpu could be online when get from policy->cpus, but offline when checked here, since hotplug is able to happen during the period. > mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay); > } > > see splats collection below. > > And I don't think your fix above addresses the issue for the simple > reason that if cpus go offline *before* you do get_online_cpus(), then > policy->cpus will already contain offlined cpus. I don't get it... get_online_cpus() is just stop hotplug happen after it was invoked, so unless policy->cpus is really wrong, otherwise all the cpu it masked won't go offline any more. > > Rather, a better fix would be, IMHO, to do this (it works here, of course): > > --- > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c > index 5af40ad82d23..58541b164494 100644 > --- a/drivers/cpufreq/cpufreq_governor.c > +++ b/drivers/cpufreq/cpufreq_governor.c > @@ -17,6 +17,7 @@ > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > #include > +#include > #include > #include > #include > @@ -169,7 +170,15 @@ static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data, > { > struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); > > + get_online_cpus(); This protect nothing...before we go here, the cpu could already offline, nothing changed... If you really want to confirm the policy->cpus was wrong, the way should be apply the fix I suggested, than check online in here. If hotplug could not happen but still get an offline cpu from policy->cpus, than we could say it's wrong, otherwise we proved nothing... Regards, Michael Wang > + > + if (!cpu_online(cpu)) > + goto out; > + > mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay); > + > + out: > + put_online_cpus(); > } > > void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, > -- > > > [ 94.386340] EXT4-fs (sda7): re-mounted. Opts: (null) > [ 96.520362] kvm: exiting hardware virtualization > [ 96.637687] ACPI: Preparing to enter system sleep state S5 > [ 96.643506] Disabling non-boot CPUs ... > [ 96.855499] ------------[ cut here ]------------ > [ 96.860172] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 96.868501] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 96.914238] CPU: 0 PID: 315 Comm: kworker/1:2 Tainted: G W 3.10.0-rc1+ #2 > [ 96.921969] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 96.929424] Workqueue: events od_dbs_timer > [ 96.933574] 0000000000000009 ffff88043a08bc78 ffffffff8161445c ffff88043a08bcb8 > [ 96.941085] ffffffff8103e540 ffff88043b712a80 0000000000000001 ffff88043a296400 > [ 96.948602] ffff88043b712a80 ffffffff81cdc910 0000000000000001 ffff88043a08bcc8 > [ 96.956123] Call Trace: > [ 96.958602] [] dump_stack+0x19/0x1b > [ 96.963801] [] warn_slowpath_common+0x70/0xa0 > [ 96.969858] [] warn_slowpath_null+0x1a/0x20 > [ 96.975735] [] gov_queue_work+0xf0/0x110 > [ 96.981359] [] od_dbs_timer+0xcb/0x170 > [ 96.986808] [] process_one_work+0x1fd/0x540 > [ 96.992691] [] ? process_one_work+0x192/0x540 > [ 96.998756] [] worker_thread+0x122/0x380 > [ 97.004371] [] ? rescuer_thread+0x320/0x320 > [ 97.010256] [] kthread+0xea/0xf0 > [ 97.015185] [] ? flush_kthread_worker+0x150/0x150 > [ 97.021605] [] ret_from_fork+0x7c/0xb0 > [ 97.027049] [] ? flush_kthread_worker+0x150/0x150 > [ 97.033457] ---[ end trace d36d91c626ac81a0 ]--- > [ 97.039221] ------------[ cut here ]------------ > [ 97.039227] ------------[ cut here ]------------ > [ 97.039229] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 97.039243] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 97.039245] CPU: 4 PID: 82 Comm: kworker/2:1 Tainted: G W 3.10.0-rc1+ #2 > [ 97.039245] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 97.039248] Workqueue: events od_dbs_timer > [ 97.039250] 0000000000000009 ffff88043b5cfc78 ffffffff8161445c ffff88043b5cfcb8 > [ 97.039251] ffffffff8103e540 ffff88043b712a80 0000000000000002 ffff88043a295e00 > [ 97.039253] ffff88043b712a80 ffffffff81cdc910 0000000000000002 ffff88043b5cfcc8 > [ 97.039253] Call Trace: > [ 97.039255] [] dump_stack+0x19/0x1b > [ 97.039257] [] warn_slowpath_common+0x70/0xa0 > [ 97.039258] [] warn_slowpath_null+0x1a/0x20 > [ 97.039259] [] gov_queue_work+0xf0/0x110 > [ 97.039261] [] od_dbs_timer+0xcb/0x170 > [ 97.039263] [] process_one_work+0x1fd/0x540 > [ 97.039264] [] ? process_one_work+0x192/0x540 > [ 97.039265] [] worker_thread+0x122/0x380 > [ 97.039267] [] ? rescuer_thread+0x320/0x320 > [ 97.039268] [] kthread+0xea/0xf0 > [ 97.039269] [] ? flush_kthread_worker+0x150/0x150 > [ 97.039270] [] ret_from_fork+0x7c/0xb0 > [ 97.039272] [] ? flush_kthread_worker+0x150/0x150 > [ 97.039272] ---[ end trace d36d91c626ac81a1 ]--- > [ 97.143214] nouveau E[ DRM] GPU lockup - switching to software fbcon > [ 97.318430] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 97.326804] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 97.374578] CPU: 0 PID: 98 Comm: kworker/3:1 Tainted: G W 3.10.0-rc1+ #2 > [ 97.384154] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 97.393566] Workqueue: events od_dbs_timer > [ 97.399675] 0000000000000009 ffff88043b179c78 ffffffff8161445c ffff88043b179cb8 > [ 97.409153] ffffffff8103e540 ffff88043b712a80 0000000000000003 ffff88043a295a00 > [ 97.418623] ffff88043b712a80 ffffffff81cdc910 0000000000000003 ffff88043b179cc8 > [ 97.428103] Call Trace: > [ 97.432520] [] dump_stack+0x19/0x1b > [ 97.439678] [] warn_slowpath_common+0x70/0xa0 > [ 97.447694] [] warn_slowpath_null+0x1a/0x20 > [ 97.455512] [] gov_queue_work+0xf0/0x110 > [ 97.462993] [] od_dbs_timer+0xcb/0x170 > [ 97.470259] [] process_one_work+0x1fd/0x540 > [ 97.477878] [] ? process_one_work+0x192/0x540 > [ 97.485652] [] worker_thread+0x122/0x380 > [ 97.492969] [] ? rescuer_thread+0x320/0x320 > [ 97.500565] [] kthread+0xea/0xf0 > [ 97.507167] [] ? flush_kthread_worker+0x150/0x150 > [ 97.515255] [] ret_from_fork+0x7c/0xb0 > [ 97.522389] [] ? flush_kthread_worker+0x150/0x150 > [ 97.530472] ---[ end trace d36d91c626ac81a2 ]--- > [ 97.543176] ------------[ cut here ]------------ > [ 97.547172] ------------[ cut here ]------------ > [ 97.547178] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 97.547197] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 97.547199] CPU: 7 PID: 316 Comm: kworker/5:1 Tainted: G W 3.10.0-rc1+ #2 > [ 97.547200] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 97.547202] Workqueue: events od_dbs_timer > [ 97.547204] 0000000000000009 ffff88043905dc78 ffffffff8161445c ffff88043905dcb8 > [ 97.547205] ffffffff8103e540 ffff88043b712a80 0000000000000005 ffff88043a295800 > [ 97.547206] ffff88043b712a80 ffffffff81cdc910 0000000000000005 ffff88043905dcc8 > [ 97.547207] Call Trace: > [ 97.547211] [] dump_stack+0x19/0x1b > [ 97.547214] [] warn_slowpath_common+0x70/0xa0 > [ 97.547215] [] warn_slowpath_null+0x1a/0x20 > [ 97.547216] [] gov_queue_work+0xf0/0x110 > [ 97.547218] [] od_dbs_timer+0xcb/0x170 > [ 97.547220] [] process_one_work+0x1fd/0x540 > [ 97.547221] [] ? process_one_work+0x192/0x540 > [ 97.547222] [] worker_thread+0x122/0x380 > [ 97.547224] [] ? rescuer_thread+0x320/0x320 > [ 97.547225] [] kthread+0xea/0xf0 > [ 97.547226] [] ? flush_kthread_worker+0x150/0x150 > [ 97.547228] [] ret_from_fork+0x7c/0xb0 > [ 97.547229] [] ? flush_kthread_worker+0x150/0x150 > [ 97.547230] ---[ end trace d36d91c626ac81a3 ]--- > [ 97.761326] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 97.770798] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 97.819617] CPU: 0 PID: 253 Comm: kworker/4:1 Tainted: G W 3.10.0-rc1+ #2 > [ 97.828623] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 97.837372] Workqueue: events od_dbs_timer > [ 97.842805] 0000000000000009 ffff880439529c78 ffffffff8161445c ffff880439529cb8 > [ 97.851628] ffffffff8103e540 ffff88043b712a80 0000000000000004 ffff88043a295c00 > [ 97.860445] ffff88043b712a80 ffffffff81cdc910 0000000000000004 ffff880439529cc8 > [ 97.869249] Call Trace: > [ 97.873041] [] dump_stack+0x19/0x1b > [ 97.879533] [] warn_slowpath_common+0x70/0xa0 > [ 97.886912] [] warn_slowpath_null+0x1a/0x20 > [ 97.894100] [] gov_queue_work+0xf0/0x110 > [ 97.901002] [] od_dbs_timer+0xcb/0x170 > [ 97.907706] [] process_one_work+0x1fd/0x540 > [ 97.914797] [] ? process_one_work+0x192/0x540 > [ 97.922016] [] worker_thread+0x122/0x380 > [ 97.928803] [] ? rescuer_thread+0x320/0x320 > [ 97.935837] [] kthread+0xea/0xf0 > [ 97.941900] [] ? flush_kthread_worker+0x150/0x150 > [ 97.949443] [] ret_from_fork+0x7c/0xb0 > [ 97.956027] [] ? flush_kthread_worker+0x150/0x150 > [ 97.963563] ---[ end trace d36d91c626ac81a4 ]--- > [ 97.970449] ------------[ cut here ]------------ > [ 97.976277] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 97.985762] Modules linked in: ext2 vfat fat loop usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 98.035051] CPU: 0 PID: 102 Comm: kworker/6:1 Tainted: G W 3.10.0-rc1+ #2 > [ 98.044067] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 98.052834] Workqueue: events od_dbs_timer > [ 98.058285] 0000000000000009 ffff88043b6f3c78 ffffffff8161445c ffff88043b6f3cb8 > [ 98.067114] ffffffff8103e540 ffff88043b712a80 0000000000000006 ffff88043a295600 > [ 98.075924] ffff88043b712a80 ffffffff81cdc910 0000000000000006 ffff88043b6f3cc8 > [ 98.084735] Call Trace: > [ 98.088518] [] dump_stack+0x19/0x1b > [ 98.095024] [] warn_slowpath_common+0x70/0xa0 > [ 98.102386] [] warn_slowpath_null+0x1a/0x20 > [ 98.109565] [] gov_queue_work+0xf0/0x110 > [ 98.116502] [] od_dbs_timer+0xcb/0x170 > [ 98.123253] [] process_one_work+0x1fd/0x540 > [ 98.130394] [] ? process_one_work+0x192/0x540 > [ 98.137667] [] worker_thread+0x122/0x380 > [ 98.144456] [] ? rescuer_thread+0x320/0x320 > [ 98.151510] [] kthread+0xea/0xf0 > [ 98.157583] [] ? flush_kthread_worker+0x150/0x150 > [ 98.165143] [] ret_from_fork+0x7c/0xb0 > [ 98.171730] [] ? flush_kthread_worker+0x150/0x150 > [ 98.179282] ---[ end trace d36d91c626ac81a5 ]--- > [ 98.185098] ------------[ cut here ]------------ > [ 98.190903] WARNING: at drivers/cpufreq/cpufreq_governor.c:172 gov_queue_work+0xf0/0x110() > [ 98.200387] Modules linked in: ext2 vfat fat loop > [ 98.205029] nouveau W[ PFIFO][0000:03:00.0] unknown intr 0x00400000, ch 1 > [ 98.214563] usbhid snd_hda_codec_hdmi coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec ehci_pci xhci_hcd ehci_hcd usbcore crc32_pclmul crc32c_intel snd_hwdep snd_pcm snd_page_alloc snd_timer ghash_clmulni_intel snd aesni_intel aes_x86_64 glue_helper sb_edac edac_core acpi_cpufreq mperf pcspkr lrw gf128mul ablk_helper cryptd iTCO_wdt iTCO_vendor_support evdev soundcore lpc_ich mfd_core processor dcdbas i2c_i801 usb_common button microcode > [ 98.258886] CPU: 0 PID: 318 Comm: kworker/7:1 Tainted: G W 3.10.0-rc1+ #2 > [ 98.267919] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 > [ 98.276689] Workqueue: events od_dbs_timer > [ 98.282147] 0000000000000009 ffff88043969dc78 ffffffff8161445c ffff88043969dcb8 > [ 98.290991] ffffffff8103e540 ffff88043b712a80 0000000000000007 ffff88043a295200 > [ 98.299832] ffff88043b712a80 ffffffff81cdc910 0000000000000007 ffff88043969dcc8 > [ 98.308671] Call Trace: > [ 98.312471] [] dump_stack+0x19/0x1b > [ 98.318982] [] warn_slowpath_common+0x70/0xa0 > [ 98.326376] [] warn_slowpath_null+0x1a/0x20 > [ 98.333577] [] gov_queue_work+0xf0/0x110 > [ 98.340482] [] od_dbs_timer+0xcb/0x170 > [ 98.347160] [] process_one_work+0x1fd/0x540 > [ 98.354232] [] ? process_one_work+0x192/0x540 > [ 98.361471] [] worker_thread+0x122/0x380 > [ 98.368260] [] ? rescuer_thread+0x320/0x320 > [ 98.375309] [] kthread+0xea/0xf0 > [ 98.381385] [] ? flush_kthread_worker+0x150/0x150 > [ 98.388951] [] ret_from_fork+0x7c/0xb0 > [ 98.395546] [] ? flush_kthread_worker+0x150/0x150 > [ 98.403097] ---[ end trace d36d91c626ac81a6 ]--- > [ 98.409180] Power down. > [ 98.413109] acpi_power_off called > -- 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/