Messages in this thread | | | Date | Fri, 01 Mar 2013 17:39:51 +0800 | From | Simon Jeons <> | Subject | Re: [PATCH] x86: mm: Check if PUD is large when validating a kernel address v2 |
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On 03/01/2013 05:35 PM, Chen Gong wrote: > On Fri, Mar 01, 2013 at 05:21:35PM +0800, Simon Jeons wrote: >> Date: Fri, 01 Mar 2013 17:21:35 +0800 >> From: Simon Jeons <simon.jeons@gmail.com> >> To: Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@kernel.org>, Andrew >> Morton <akpm@linux-foundation.org>, 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 >> >> On 03/01/2013 05:15 PM, Chen Gong wrote: >>> 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 <simon.jeons@gmail.com> >>>> To: Mel Gorman <mgorman@suse.de> >>>> CC: Ingo Molnar <mingo@kernel.org>, Andrew Morton >>>> <akpm@linux-foundation.org>, 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 >>>> >>>> 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: [<ffffffff8103157e>] 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 sunrpc 8021q garp stp llc cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf microcode fuse nls_iso8859_1 nls_cp437 vfat fat loop dm_mod ioatdma ipv6 ipv6_lib igb dca i7core_edac edac_core i2c_i801 i2c_core 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 mbcache 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_generic ata_piix libata megaraid_sas scsi_mod >>>>> >>>>> Pid: 16196, comm: Hibackp Not tainted 3.0.13-0.27-default #1 IBM System x3550 M3 -[7944 K3G]-/94Y7614 >>>>> RIP: 0010:[<ffffffff8103157e>] [<ffffffff8103157e>] kern_addr_valid+0xbe/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:0000000000000000 >>>>> 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 ffff8808eb9ba600) >>>>> Stack: >>>>> ffffffff811b8aaa 0000000000004000 ffff880943fea480 ffff8808ef2bae50 >>>>> ffff880943d32980 fffffffffffffffb ffff8808ef2bae40 ffff88094165ff50 >>>>> 0000000000004000 000000000056ebe0 ffffffff811ad847 000000000056ebe0 >>>>> Call Trace: >>>>> [<ffffffff811b8aaa>] read_kcore+0x17a/0x370 >>>>> [<ffffffff811ad847>] proc_reg_read+0x77/0xc0 >>>>> [<ffffffff81151687>] vfs_read+0xc7/0x130 >>>>> [<ffffffff811517f3>] sys_read+0x53/0xa0 >>>>> [<ffffffff81449692>] 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 >>>> Do you mean there is one page which is 1G? >>>> >>> 1GB support in native kernel is started from 2.6.27 with these 2 commits: >> Why call kernel native? Which kend of kernel is not native? > relative to VMM like Xen.
Oh, I see. Thanks. :)
> >>> 39c11e6 and b4718e6. For Intel CPU, from Westmere it supports 1GB page. >>> BTW, IBM System x3550 M3 is a Westmere based system. >> Is it only used in hugetlbfs page? > Yes by now.
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