Re: SLUB doesn't work with kdump kernel on Cell

From: Lucio Correia
Date: Thu Aug 09 2007 - 09:56:29 EST

On Wed, 2007-08-08 at 23:10 +0200, Arnd Bergmann wrote:
> On Wednesday 08 August 2007, Lucio Correia wrote:
> > DMA 0 -> 12288
> > Normal 12288 -> 12288
> > early_node_map[2] active PFN ranges
> > 0: 0 -> 2560
> > 1: 12287 -> 12288
>
> As Christoph found, this memory map is really strange. Other machines
> have something like
>
> Zone PFN ranges:
> DMA 0 -> 16384
> Normal 16384 -> 16384
> early_node_map[2] active PFN ranges
> 0: 0 -> 8192
> 1: 8192 -> 16384
>
> Lucio,
> What code builds the memory map that gets passed to the kdump kernel?

The function default_machine_kexec_prepare in
arch/powerpc/kernel/machine_kexec_64.c.


> Does the original kernel see the same map on your machine?

For the original kernel the map is ok:

Zone PFN ranges:
DMA 0 -> 16384
Normal 16384 -> 16384
early_node_map[2] active PFN ranges
0: 0 -> 8192
1: 8192 -> 16384


> Arnd <><

I also tried to pass maxcpus=1 for the command line of second kernel,
and it didn't work. How can I alternatively disable the node?

Loaded the kernel and crashed it with the commands:


[root@localhost ~]# kexec -p /boot/vmlinux-2.6.22-5.20070711bsckdump
--initrd=/boot/initrd-2.6.22-5.20070711bsckdump.img --append="maxcpus=1"
get memory ranges:1
Modified cmdline:maxcpus=1 elfcorehdr=41984K savemaxmem=1024M
root=LABEL=/1
segment[0].mem:0x2000000 memsz:9371648
segment[1].mem:0x28f0000 memsz:65536
segment[2].mem:0x2900000 memsz:65536
segment[3].mem:0x2910000 memsz:65536
segment[4].mem:0x2920000 memsz:3735552
segment[5].mem:0x9ff0000 memsz:65536

[root@localhost ~]# echo c > /proc/sysrq-trigger


The boot output for the second kernel is:


SysRq : Trigger a crashdump
Sending IPI to other cpus...
Starting Linux PPC64 #1 SMP Tue Jul 17 09:30:52 CEST 2007
-----------------------------------------------------
ppc64_pft_size = 0x0
physicalMemorySize = 0xa010000
ppc64_caches.dcache_line_size = 0x80
ppc64_caches.icache_line_size = 0x80
htab_address = 0xc000000009800000
htab_hash_mask = 0x7fff
physical_start = 0x2000000
-----------------------------------------------------
Linux version 2.6.22-5.20070711bsckdump
(cellbld@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) (gcc version 4.1.2 20070502
(Red Hat 4.1.27
*** 0000 : CF000012

*** 0000 : Setup Arch
[boot]0012 Setup Arch
no ISA IO ranges or unexpected isa range,mapping 64k
mmio NVRAM, 1024k at 0x2401fb00000 mapped to d000080080060000
Zone PFN ranges:
DMA 0 -> 12288
Normal 12288 -> 12288
early_node_map[2] active PFN ranges
0: 0 -> 2560
1: 12287 -> 12288
*** 0000 : CF000015

*** 0000 : Setup Done
[boot]0015 Setup Done
Built 2 zonelists. Total pages: 2559
Kernel command line: maxcpus=1 elfcorehdr=41984K savemaxmem=1024M
root=LABEL=/1
IIC for CPU 0 target id 0xe : /interrupt-controller@20000508400
IIC for CPU 1 target id 0xf : /interrupt-controller@20000508400
IIC for CPU 2 target id 0x1e : /interrupt-controller@30000508400
IIC for CPU 3 target id 0x1f : /interrupt-controller@30000508400
spider_pic: node 0, addr:
0x24000008000 /interrupt-controller@24000008000
spider_pic: node 1, addr:
0x34000008000 /interrupt-controller@34000008000
PID hash table entries: 1024 (order: 10, 8192 bytes)
Console: colour dummy device 80x25
console handover: boot [udbg0] -> real [tty0]
Using Cell machine description
Found initrd at 0xc000000002920000:0xc000000002cb0000
Starting Linux PPC64 #1 SMP Tue Jul 17 09:30:52 CEST 2007
-----------------------------------------------------
ppc64_pft_size = 0x0
physicalMemorySize = 0xa010000
ppc64_caches.dcache_line_size = 0x80
ppc64_caches.icache_line_size = 0x80
htab_address = 0xc000000009800000
htab_hash_mask = 0x7fff
physical_start = 0x2000000
-----------------------------------------------------
Linux version 2.6.22-5.20070711bsckdump
(cellbld@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) (gcc version 4.1.2 20070502
(Red Hat 4.1.27
*** 0000 : CF000012

*** 0000 : Setup Arch
[boot]0012 Setup Arch
no ISA IO ranges or unexpected isa range,mapping 64k
mmio NVRAM, 1024k at 0x2401fb00000 mapped to d000080080060000
Zone PFN ranges:
DMA 0 -> 12288
Normal 12288 -> 12288
early_node_map[2] active PFN ranges
0: 0 -> 2560
1: 12287 -> 12288
*** 0000 : CF000015

*** 0000 : Setup Done
[boot]0015 Setup Done
Built 2 zonelists. Total pages: 2559
Kernel command line: maxcpus=1 elfcorehdr=41984K savemaxmem=1024M
root=LABEL=/1
IIC for CPU 0 target id 0xe : /interrupt-controller@20000508400
IIC for CPU 1 target id 0xf : /interrupt-controller@20000508400
IIC for CPU 2 target id 0x1e : /interrupt-controller@30000508400
IIC for CPU 3 target id 0x1f : /interrupt-controller@30000508400
spider_pic: node 0, addr:
0x24000008000 /interrupt-controller@24000008000
spider_pic: node 1, addr:
0x34000008000 /interrupt-controller@34000008000
PID hash table entries: 1024 (order: 10, 8192 bytes)
Console: colour dummy device 80x25
console handover: boot [udbg0] -> real [tty0]
Dentry cache hash table entries: 32768 (order: 2, 262144 bytes)
Inode-cache hash table entries: 16384 (order: 1, 131072 bytes)
freeing bootmem node 0
freeing bootmem node 1
Memory: 112576k/163904k available (6400k kernel code, 51328k reserved,
1344k data, 870k bss, 448k init)
------------[ cut here ]------------
kernel BUG at mm/slub.c:1802!
cpu 0x0: Vector: 700 (Program Check) at [c000000002793a60]
pc: c000000002106f94: .kmem_cache_open+0x1e8/0x338
lr: c000000002106f88: .kmem_cache_open+0x1dc/0x338
sp: c000000002793ce0
msr: 9000000000029032
current = 0xc0000000026643f0
paca = 0xc000000002664d00
pid = 0, comm = swapper
kernel BUG at mm/slub.c:1802!
enter ? for help
[c000000002793da0] c00000000210788c .create_kmalloc_cache+0x70/0xe8
[c000000002793e50] c0000000025f65cc .kmem_cache_init+0x40/0x16c
[c000000002793ee0] c0000000025d09a8 .start_kernel+0x2f8/0x404
[c000000002793f90] c000000002008534 .start_here_common+0x60/0xac
0:mon>


--
Lucio Correia
Software Engineer
IBM LTC Brazil

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