>>> On 01.09.10 at 12:21, MaoXiaoyun <tinnycloud@xxxxxxxxxxx> wrote:
> I myself did below test. in page_alloc.c.
>
> check_page will panic on all pages which the 6th character in its adddress
> is '3', i used to indicate which line paniced.
>
>
>
> Below output indicates the panic comes from line 558, and the page address
> is ffff82f600002040, while its next page
>
> is ffff8315ffffffe0, compare to the panic address in previous
> panic(ffff8315ffffffe4), which is very similar.
>
>
>
> I think this should imply something.
No, you didn't do it right. When merging backwards pg->list.next may
validly be PAGE_LIST_NULL, and hence calling check_page() with it
passed as second argument isn't correct. Similarly when forward
merging, pgt->list.prev may validly be PAGE_LIST_NULL.
Jan
>
>
>
> ---------------------------------------
>
> (XEN) -----------18
> (XEN) System RAM: 24542MB (25131224kB)
> (XEN) SRAT: No PXM for e820 range: 0000000000000000 - 000000000009a7ff
> (XEN) SRAT: SRAT not used.
> (XEN) ----------------pgb ffff82f600002040 pg ffff8315ffffffe0, mask 1, order
> 0, 0
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) xmao invalid page address assigned
> (XEN) ****************************************
> (XEN)
>
>
>
> ----------------------------------------------------
>
> 485 static int check_page(struct page_info* pgb, struct page_info* pg,
> unsigned long mask, unsigned int order, int i){
> 486
> 487 if((unsigned long)pg & 0x0000020000000000 &&
> 488 (unsigned long)pg & 0x0000010000000000
> 489 ){
> 490 printk("----------------pgb %p pg %p, mask %lx, order
> %d, %d\n", pgb,
> pg, mask, order, i);
> 491 panic("xmao invalid page address assigned \n");
> 492 }
> 493 return 0;
> 494 }
>
>
>
> 549 if ( (page_to_mfn(pg) & mask) )
> 550 {
> 551 /* Merge with predecessor block? */
> 552 if ( !mfn_valid(page_to_mfn(pg-mask)) ||
> 553 !page_state_is(pg-mask, free) ||
> 554 (PFN_ORDER(pg-mask) != order) )
> 555 break;
> 556 pg -= mask;
> 557
> 558 check_page(pg, pdx_to_page(pg->list.next), mask, order, 0);
>
>
>
> 559 check_page(pg, pdx_to_page(pg->list.prev), mask, order, 1);
> 560
> 561 page_list_del(pg, &heap(node, zone, order));
> 562 }
> 563 else
> 564 {
> 565 /* Merge with successor block? */
> 566 if ( !mfn_valid(page_to_mfn(pg+mask)) ||
> 567 !page_state_is(pg+mask, free) ||
> 568 (PFN_ORDER(pg+mask) != order) )
> 569 break;
> 570
> 571 pgt = pg + mask;
> 572 check_page(pg, pdx_to_page(pgt->list.next), mask, order, 2);
> 573 check_page(pg, pdx_to_page(pgt->list.prev), mask, order, 3);
> 574
>
>> Date: Wed, 1 Sep 2010 10:58:54 +0100
>> Subject: Re: [Xen-devel] Xen-unstable panic: FATAL PAGE FAULT
>> From: keir.fraser@xxxxxxxxxxxxx
>> To: tinnycloud@xxxxxxxxxxx; jbeulich@xxxxxxxxxx
>> CC: xen-devel@xxxxxxxxxxxxxxxxxxx
>>
>> Hm, well, it is a bit weird. The check in init_heap_pages() ought to prevent
>> merging across node boundaries. Nonetheless the code is simpler and more
>> obvious if we put a further merging constraint in free_heap_pages() instead.
>> It's also correcter, since I'm not sure that the
>> phys_to_nid(page_to_maddr(pg-1)) in init_heap_pages() won't possibly BUG out
>> if pg-1 is not a RAM page and is not in a known NUMA node range.
>>
>> Please give the attached patch a spin. (You should revert the previous
>> patch, of course).
>>
>> Thanks,
>> Keir
>>
>> On 01/09/2010 10:23, "MaoXiaoyun" <tinnycloud@xxxxxxxxxxx> wrote:
>>
>> > Well. It did crash on every startup.
>> >
>> > below is what I got.
>> > ---------------------------------------------------
>> > root (hd0,0)
>> > Filesystem type is ext2fs, partition type 0x83
>> > kernel /xen-4.0.0.gz msi=1 iommu=off x2apic=off hap=0 dom0_mem=10240M
>> > dom0_max_
>> > vcpus=4 dom0_vcpus_pin console=com1,vga com1=115200,8n1 conswitch=ax
> noreboot
>> > [Multiboot-elf, <0x100000:0x152000:0x148000>, shtab=0x39a078,
>> > entry=0x100000
>> > ]
>> > module /vmlinuz-2.6.31.13-pvops-patch ro root=LABEL=/ hda=noprobe
>> > console=hvc0
>> > [Multiboot-module @ 0x39b000, 0x3214d0 bytes]
>> >
>> >
>> > __ __ _ _
>> > ___ ___
>> > \ \/ /___ _ __ | || | / _ \ / _ \ *
>> > \ // _ \ '_ \ | || |_| | | | | | | *
>> > / \ __/ | | | |__ _| |_| | |_| | * *
>> > /_/\_\___|_| |_| |_|(_)___(_)___/ **************************************
>> > hich entry is highlighted.
>> > (XEN) Xen version 4.0.0 (root@xxxxxxxxxxxxxxxxx) (gcc version 4.1.2
> 20080704
>> > (Red Hat 4.1.2-46)) Wed Sep 1 17:13:35 CST 2010
>> > (XEN) Latest ChangeSet: unavailableto modify the kernel arguments
>> > (XEN) Command line: msi=1 iommu=off x2apic=off hap=0 dom0_mem=10240M
>> > dom0_max_vcpus=4 dom0_vcpus_pin console=com1,vga com1=115200,8n1
> conswitch=ax
>> > noreboot
>> > (XEN) Video information:
>> > (XEN) VGA is text mode 80x25, font 8x16automatically in 3 seconds.
>> > (XEN) VBE/DDC methods: none; EDID transfer time: 0 seconds
>> > (XEN) EDID info not retrieved because no DDC retrieval method detected
>> > (XEN) Disc information:
>> > (XEN) Found 6 MBR signatures
>> > (XEN) Found 6 EDD information structures
>> > (XEN) Xen-e820 RAM map:
>> > (XEN) 0000000000000000 - 000000000009a800 (usable)
>> > (XEN) 000000000009a800 - 00000000000a0000 (reserved)
>> > (XEN) 00000000000e4bb0 - 0000000000100000 (reserved)
>> > (XEN) 0000000000100000 - 00000000bf790000 (usable)
>> > (XEN) 00000000bf790000 - 00000000bf79e000 (ACPI data)
>> > (XEN) 00000000bf79e000 - 00000000bf7d0000 (ACPI NVS)
>> > (XEN) 00000000bf7d0000 - 00000000bf7e0000 (reserved)
>> > (XEN) 00000000bf7ec000 - 00000000c0000000 (reserved)
>> > (XEN) 00000000e0000000 - 00000000f0000000 (reserved)
>> > (XEN) 00000000fee00000 - 00000000fee01000 (reserved)
>> > (XEN) 00000000fff00000 - 0000000100000000 (reserved)
>> > (XEN) 0000000100000000 - 0000000640000000 (usable)
>> > (XEN) --------------849
>> > (XEN) --------------849
>> > (XEN) --------------849
>> > (XEN) ACPI: RSDP 000F9DD0, 0024 (r2 ACPIAM)
>> > (XEN) ACPI: XSDT BF790100, 005C (r1 112309 XSDT1113 20091123 MSFT 97)
>> > (XEN) ACPI: FACP BF790290, 00F4 (r4 112309 FACP1113 20091123 MSFT 97)
>> > (XEN) ACPI: DSDT BF7904B0, 4D6A (r2 CTSAV CTSAV122 122 INTL 20051117)
>> > (XEN) ACPI: FACS BF79E000, 0040
>> > (XEN) ACPI: APIC BF790390, 00D8 (r2 112309 APIC1113 20091123 MSFT 97)
>> > (XEN) ACPI: MCFG BF790470, 003C (r1 112309 OEMMCFG 20091123 MSFT 97)
>> > (XEN) ACPI: OEMB BF79E040, 007A (r1 112309 OEMB1113 20091123 MSFT 97)
>> > (XEN) ACPI: SRAT BF79A4B0, 01D0 (r1 112309 OEMSRAT 1 INTL 1)
>> > (XEN) ACPI: HPET BF79A680, 0038 (r1 112309 OEMHPET 20091123 MSFT 97)
>> > (XEN) ACPI: SSDT BF7A1A00, 0363 (r1 DpgPmm CpuPm 12 INTL 20051117)
>> > (XEN) --------------847
>> > (XEN) ---------srat enter
>> > (XEN) ---------prepare enter into pfn
>> > (XEN) -------in pfn
>> > (XEN) -------hole shift returned
>> > (XEN) --------------849
>> > (XEN) System RAM: 24542MB (25131224kB)
>> > (XEN) Unknown interrupt (cr2=0000000000000000)
>> > (XEN) 00000000000000ab 0000000000000000 ffff82f600004020
>> > 00007d0a00000000 ffff82f600004000 0000000000000020 0000000000201000
>> > 0000000000000000 ffffffffffffffff 0000000000000000 0000000000000008
>> > 0000000000000000 00000000000001ff 00000000000001ff 0000000000000000
>> > ffff82c480115787 000000000000e008 0000000000010002 ffff82c48035fd18
>> > 0000000000000000 ffff82c48011536a 0000000000000000 0000000000000000
>> > 0000000000000163 0000000900000000 00000000000000ab 0000000000000201
>> > 0000000000000000 0000000000000100 ffff82f600004020 0000000000000eff
>> > 0000000000000000 ffff82c480115e60 0000000000000000 ffff82f600002020
>> > 0000000000001000 0000000000000004 0000000000000080 0000000000000001
>> > ffff82c48020be8d ffff830000100000 0000000000000008 0000000000000000
>> > 0000000000000000 ffffffffffffffff 0000000000000101 ffff82c48022d8fc
>> > 0000000000540000 00000000005fde36 0000000000540000 0000000000100000
>> > 0000000100000000 0000000000000010 ffff82c48024deb4 ffff82c4802404f7
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 ffff8300bf568ff8 ffff8300bf569ff8 000000000022a630
>> > 000000000022a695 0000000000087f00 0000000000000000 ffff830000087fc0
>> > 00000000005fde36 000000000087b6d0 0000000000d44000 0000000001000000
>> > 0000000000000000 ffffffffffffffff ffff830000087f00 0000100000000000
>> > 0000000800000000 000000010000006e 0000000000000003 00000000000002f8
>> > 0000000000000000 0000000000000000 0000000000067ebc 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 ffff82c4801000b5
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> > 0000000000000000 0000000000000000 00000000fffff000
>> >
>> >> Date: Wed, 1 Sep 2010 09:49:18 +0100
>> >> Subject: Re: [Xen-devel] Xen-unstable panic: FATAL PAGE FAULT
>> >> From: keir.fraser@xxxxxxxxxxxxx
>> >> To: JBeulich@xxxxxxxxxx
>> >> CC: tinnycloud@xxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
>> >>
>> >> On 01/09/2010 09:02, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:
>> >>
>> >>>> Well I agree with your logic anyway. So I don't see that this can be the
>> >>>> cause of MaoXiaoyun's bug. At least not directly. But then I'm stumped
>> >>>> as
>> >>>> to
>> >>>> why the page arithmetic and checks in free_heap_pages are (apparently)
>> >>>> resulting in a page pointer way outside the frame-table region and
>> >>>> actually
>> >>>> in the directmap region.
>> >>>
>> >>> There must be some unchecked use of PAGE_LIST_NULL, i.e.
>> >>> running off a list end without taking notice (0xffff8315ffffffe4
>> >>> exactly corresponds with that).
>> >>
>> >> Okay, my next guess then is that we are deleting a chunk from the wrong
> list
>> >> head. I don't see any check that the adjacent chunks we are considering to
>> >> merge are from the same node and zone. I suppose the zone logic does just
>> >> work as we're dealing with 2**x aligned and sized regions. But, shouldn't
>> >> the merging logic in free_heap_pages be checking that the merging
>> >> candidate
>> >> is from the same NUMA node? I see I have an ASSERTion later in the same
>> >> function, but it's too weak and wishful I suspect.
>> >>
>> >> MaoXiaoyun: can you please test with the attached patch? If I'm right, you
>> >> will crash on one of the BUG_ON checks that I added, rather than crashing
> on
>> >> a pointer dereference. You may even crash during boot. Anyhow, what is
>> >> interesting is whether this patch always makes you crash on BUG_ON before
>> >> you would normally crash on pointer dereference. If so this is trivial to
>> >> fix.
>> >>
>> >> Thanks,
>> >> Keir
>> >>
>> >
>>
>
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