From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx188.postini.com [74.125.245.188]) by kanga.kvack.org (Postfix) with SMTP id C286F6B0002 for ; Fri, 1 Mar 2013 04:17:22 -0500 (EST) Date: Fri, 1 Mar 2013 04:15:13 -0500 From: Chen Gong Subject: Re: [PATCH] x86: mm: Check if PUD is large when validating a kernel address v2 Message-ID: <20130301091513.GA11787@gchen.bj.intel.com> References: <20130211145236.GX21389@suse.de> <20130213110202.GI4100@suse.de> <51304E29.40900@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="xHFwDpU9dbj6ez1V" Content-Disposition: inline In-Reply-To: <51304E29.40900@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Simon Jeons Cc: Mel Gorman , Ingo Molnar , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com, mhocko@suse.cz, hannes@cmpxchg.org --xHFwDpU9dbj6ez1V Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 01, 2013 at 02:43:53PM +0800, Simon Jeons wrote: > Date: Fri, 01 Mar 2013 14:43:53 +0800 > From: Simon Jeons > To: Mel Gorman > CC: Ingo Molnar , Andrew Morton > , linux-kernel@vger.kernel.org, > linux-mm@kvack.org, riel@redhat.com, mhocko@suse.cz, hannes@cmpxchg.org > Subject: Re: [PATCH] x86: mm: Check if PUD is large when validating a > kernel address v2 > User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130221 > Thunderbird/17.0.3 >=20 > On 02/13/2013 07:02 PM, Mel Gorman wrote: > >Andrew or Ingo, please pick up. > > > >Changelog since v1 > > o Add reviewed-bys and acked-bys > > > >A user reported a bug whereby a backup process accessing /proc/kcore > >caused an oops. > > > > BUG: unable to handle kernel paging request at ffffbb00ff33b000 > > IP: [] kern_addr_valid+0xbe/0x110 > > PGD 0 > > Oops: 0000 [#1] SMP > > CPU 6 > > Modules linked in: af_packet nfs lockd fscache auth_rpcgss nfs_acl sun= rpc 8021q garp stp llc cpufreq_conservative cpufreq_userspace cpufreq_power= save acpi_cpufreq mperf microcode fuse nls_iso8859_1 nls_cp437 vfat fat loo= p dm_mod ioatdma ipv6 ipv6_lib igb dca i7core_edac edac_core i2c_i801 i2c_c= ore cdc_ether usbnet bnx2 mii iTCO_wdt iTCO_vendor_support shpchp rtc_cmos = pci_hotplug tpm_tis sg tpm pcspkr tpm_bios serio_raw button ext3 jbd mbcach= e uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif usb_common processor thermal_= sys hwmon scsi_dh_emc scsi_dh_rdac scsi_dh_alua scsi_dh_hp_sw scsi_dh ata_g= eneric ata_piix libata megaraid_sas scsi_mod > > > > Pid: 16196, comm: Hibackp Not tainted 3.0.13-0.27-default #1 IBM Syste= m x3550 M3 -[7944 K3G]-/94Y7614 > > RIP: 0010:[] [] kern_addr_valid+0= xbe/0x110 > > RSP: 0018:ffff88094165fe80 EFLAGS: 00010246 > > RAX: 00003300ff33b000 RBX: ffff880100000000 RCX: 0000000000000000 > > RDX: 0000000100000000 RSI: ffff880000000000 RDI: ff32b300ff33b400 > > RBP: 0000000000001000 R08: 00003ffffffff000 R09: 0000000000000000 > > R10: 22302e31223d6e6f R11: 0000000000000246 R12: 0000000000001000 > > R13: 0000000000003000 R14: 0000000000571be0 R15: ffff88094165ff50 > > FS: 00007ff152d33700(0000) GS:ffff88097f2c0000(0000) knlGS:0000000000= 000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > > CR2: ffffbb00ff33b000 CR3: 00000009405a3000 CR4: 00000000000006e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > Process Hibackp (pid: 16196, threadinfo ffff88094165e000, task ffff880= 8eb9ba600) > > Stack: > > ffffffff811b8aaa 0000000000004000 ffff880943fea480 ffff8808ef2bae50 > > ffff880943d32980 fffffffffffffffb ffff8808ef2bae40 ffff88094165ff50 > > 0000000000004000 000000000056ebe0 ffffffff811ad847 000000000056ebe0 > > Call Trace: > > [] read_kcore+0x17a/0x370 > > [] proc_reg_read+0x77/0xc0 > > [] vfs_read+0xc7/0x130 > > [] sys_read+0x53/0xa0 > > [] system_call_fastpath+0x16/0x1b > > > >Investigation determined that the bug triggered when reading system RAM > >at the 4G mark. On this system, that was the first address using 1G pages >=20 > Do you mean there is one page which is 1G? >=20 1GB support in native kernel is started from 2.6.27 with these 2 commits: 39c11e6 and b4718e6. For Intel CPU, from Westmere it supports 1GB page. BTW, IBM System x3550 M3 is a Westmere based system. --xHFwDpU9dbj6ez1V Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJRMHGhAAoJEI01n1+kOSLHfjAP/jtqxHLGODFr/SR89RQKdt4m /KA2gqxyVhoHjrPpezO6mT7QAKg8aoNsKfkWRGNmRph10bI1ZBRM5w1V9QP8+tcL wLp6fnqy8o7QlD9JDIVR7IRRShFc1tX8f+Vba9O+RK141X2WANj5OrEbonq8bkNr ImnJGXWJvqAU+e24UswJurcITVJPCDg8YwnTkhJmHv6XA8muh4SzMrDYTxT7zXoF D27S17HQbJP0t98vHmep2XsgiW68HB9+TCyUbLJE4eIm9wrMi+/EG94xGCG6v2T5 0hOzLIG+riLb+SkIGd2bMzfYnSua/FyontYaoVjHSEXuY+TUBmUlY4ewpM9i28fq P6f0MH7injd9ddga/7l26rS3dSdrxPdY3mvlYy5Zp21giDivvCEG4ScqvZlnd+Jf wgp2sRqwGL/O4mZqtmLgZXiOxXlyJTfgDEKSFt20+TGmldiGNxKzjAmfLri2oDMU JS3PFDqdBJroI+SgAzHvWVg1Tz1aVDDY6H5gbl+Y7Z4I1uJRaZYgKFZNvAJLpwPL L3xcCm76tv8wAPjY/PU2BTflVhTbAXU673AgyHZf8IVFiG+eDQTU/3U2DvXh6nQD Pmx7OsW1GWEMwD0t20VvHgImzOb5qggh0djch5BZqhppFTWltuWDxPLtgZB+3CHU c4qvxlAw7aWcZXRyd2CN =ZjGZ -----END PGP SIGNATURE----- --xHFwDpU9dbj6ez1V-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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