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Message-ID: <4F8DA9FC.5020208@linux.vnet.ibm.com> Date: Tue, 17 Apr 2012 23:05:56 +0530 From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com> To: Borislav Petkov <bp@...64.org> CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Andreas Herrmann <andreas.herrmann3@....com>, Kay Sievers <kay.sievers@...y.org>, Dave Jones <davej@...hat.com>, linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, tigran@...azian.fsnet.co.uk, hpa@...or.com, x86@...nel.org, gene.heskett@...il.com Subject: Re: [PATCH 2/2] x86, microcode: Ensure that module is only loaded for On 04/17/2012 08:20 PM, Borislav Petkov wrote: > On Tue, Apr 17, 2012 at 07:41:22PM +0530, Srivatsa S. Bhat wrote: >> On 04/16/2012 07:13 PM, Borislav Petkov wrote: >> >>> On Mon, Apr 16, 2012 at 02:12:00PM +0530, Srivatsa S. Bhat wrote: >>>> I guess a similar change in intel microcode driver would also be >>>> worthwhile, right? If so, then the below patch might be useful: >>> >>> AFAICT, you'd need to test this on a box which is not supported (family >>> check below). Or you can tweak the family check so that it doesn't >>> apply and run it on a test box of yours to see whether the module still >>> unloads properly in the error case (and doesn't remain loaded as in >>> our case due to something in sysfs remaining registered although it >>> shouldn't). >>> >> Judging by the nature of the code itself, its evident that this problem >> is not restricted to AMD alone. In any case, I went ahead and did the >> (tweaked) test that you suggested and here is the result: >> >> 1. dmesg logs : >> [ 21.912451] microcode: CPU0 not a capable Intel processor >> [ 21.916028] microcode: CPU1 not a capable Intel processor >> [ 21.934624] microcode: CPU2 not a capable Intel processor >> [ 21.940276] microcode: CPU3 not a capable Intel processor >> [ 21.946023] microcode: CPU4 not a capable Intel processor >> [ 21.951678] microcode: CPU5 not a capable Intel processor >> [ 21.957326] microcode: CPU6 not a capable Intel processor >> [ 21.962935] microcode: CPU7 not a capable Intel processor >> [ 21.968611] microcode: CPU8 not a capable Intel processor >> [ 21.974212] microcode: CPU9 not a capable Intel processor >> [ 21.979842] microcode: CPU10 not a capable Intel processor >> [ 21.985577] microcode: CPU11 not a capable Intel processor >> [ 21.991323] microcode: CPU12 not a capable Intel processor >> [ 21.997055] microcode: CPU13 not a capable Intel processor >> [ 22.002774] microcode: CPU14 not a capable Intel processor >> [ 22.008460] microcode: CPU15 not a capable Intel processor >> [ 22.014600] microcode: Microcode Update Driver: v2.00 <tigran@...azian.fsnet.co.uk>, Peter Oruba >> >> 2. lsmod | grep microcode >> microcode 117749 0 >> >> 3. rmmod microcode >> >> 4. dmesg logs: >> [ 64.297638] ------------[ cut here ]------------ >> [ 64.302332] WARNING: at fs/sysfs/group.c:142 sysfs_remove_group+0xd9/0xe0() >> [ 64.309446] Hardware name: IBM System x -[7870C4Q]- >> [ 64.309449] sysfs group ffffffffa03a5110 not found for kobject 'cpu0' >> [ 64.309451] Modules linked in: ipv6 cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf fuse loop dm_mod coretemp crc32c_intel shpchp microcode(-) cdc_ether usbnet ioatdma bnx2 mii serio_raw pcspkr pci_hotplug i2c_i801 i7core_edac i2c_core dca edac_core iTCO_wdt iTCO_vendor_support tpm_tis tpm sg tpm_bios rtc_cmos button uhci_hcd ehci_hcd usbcore usb_common sd_mod crc_t10dif edd ext3 mbcache jbd fan processor mptsas mptscsih mptbase scsi_transport_sas scsi_mod thermal thermal_sys hwmon >> [ 64.309499] Pid: 6529, comm: rmmod Not tainted 3.4.0-rc3-intelucodebroken-0.0.0.28.36b5ec9-default #2 >> [ 64.309501] Call Trace: >> [ 64.309506] [<ffffffff811fac69>] ? sysfs_remove_group+0xd9/0xe0 >> [ 64.309510] [<ffffffff811fac69>] ? sysfs_remove_group+0xd9/0xe0 >> [ 64.309516] [<ffffffff8103dd2a>] warn_slowpath_common+0x7a/0xb0 >> [ 64.309522] [<ffffffff8103de01>] warn_slowpath_fmt+0x41/0x50 >> [ 64.309526] [<ffffffff811f87b6>] ? sysfs_get_dirent+0x56/0x80 >> [ 64.309531] [<ffffffff811fac69>] sysfs_remove_group+0xd9/0xe0 >> [ 64.309538] [<ffffffffa03a2118>] mc_device_remove+0x78/0xa0 [microcode] >> [ 64.309545] [<ffffffff8134b219>] subsys_interface_unregister+0x89/0xd0 >> [ 64.309553] [<ffffffffa03a357a>] microcode_exit+0x5a/0xa4 [microcode] >> [ 64.309559] [<ffffffff810b0c8a>] sys_delete_module+0x16a/0x2b0 >> [ 64.309565] [<ffffffff810a408d>] ? trace_hardirqs_on_caller+0x12d/0x1b0 >> [ 64.309573] [<ffffffff814b36f9>] system_call_fastpath+0x16/0x1b >> [ 64.309576] ---[ end trace 748ddf8b4218f820 ]--- >> >> >> The above warning was repeated for each cpu, of course. > > Right, this is the warning we're seeing too. Applying your patch fixes > it, I s'pose? Of course.. Sorry I didn't mention it explicitly. Strictly speaking, in the patch series by Andreas, patch 1/2: gets rid of the warning, patch 2/2: ensures that the microcode module doesn't remain loaded when unsupported cpus are detected - but it does it only for AMD cpus. My patch is very much like 2/2 except that it is for the Intel cpus - if the underlying cpus are unsupported, then it ensures that the module loading fails. [The warning is already silenced by patch 1/2]. > If so, maybe x86 people would pick it up. > Ok, thanks! Regards, Srivatsa S. Bhat -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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