Hi,
I checked.. through and fond out that one of the following check condition
is failing
516 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
517 (ehdr.e_type != ET_CORE) ||
518 !vmcore_elf_check_arch(&ehdr) ||
519 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
520 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
521 ehdr.e_version != EV_CURRENT ||
522 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
523 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
524 ehdr.e_phnum == 0) {
525 printk(KERN_WARNING "Warning: Core image elf
header is not"
526 "sane:%ld\n",elfcorehdr_addr);
527 return -EINVAL
528 }
If I comment this return at line 527, then the code flows through and the
vmcore is getting generated.
However, I am facing a new issue, my user space is 32 bit and the kernel
is 64 bit. And I want to access the high memory (high_memory -
BACK_UP_SIZE) area of the previous/primary kernel. Where some log data I
had saved. The toral RAM is 8GB.
As the 32 bit pointers could not reach there... means simple file
operations lseek() , read etc are not working.. to access some region
around 8GB.
Can you please suggest me some way to reach that memory and read my raw
data from the user space.
I am able to read the data from kernel space( a simple kernel module via
/proc interface to transfer the data from kernel to user space using
physical address of the primary kernel).
Chandan Kumar
TCS Mumbai
Chandan12 K <chandan12.k at tcs.com>
Sent by: kexec-bounces at lists.infradead.org
08/13/2009 03:40 PM
To
kexec at lists.infradead.org
cc
Subject
vmcore file 0 size in x86_64
Hi,
Adding boot logs
NET: Registered protocol family 1
audit: initializing netlink socket (disabled)
type=2000 audit(1250069944.104:1): initialized
VFS: Disk quotas dquot_6.5.1
Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
Warning: Core image elf header is notsane
Kdump: vmcore not initialized
Registering unionfs 2.2-mm
msgmni has been set to 90
io scheduler noop registered
io scheduler anticipatory registered
however, similar case has already been discussed in other mailing lists
with vivek. The only difference is that, I am not using redhat system and
dont have any user level kexel tools.
https://lists.linux-foundation.org/pipermail/fastboot/2007-January/012572.html
The kernel command line of capture kernel (kexe'ed kernel) : Kernel
command line: root=/dev/nfs rw console=ttyS0,115200 ip=::::::dhcp
selinux=0 noacpi maxcpus=1 memmap=exactmap memmap=640K at 0K
memmap=64876K at 16384K elfcorehdr=81260K
Command line for the Primary kernel : root=/dev/nfs rw
console=ttyS0,115200 ip=::::::dhcp crashkernel=64M at 16M
kexec command used : kexec -p bzImage --append="root=/dev/nfs rw
console=ttyS0,115200 ip=::::::dhcp selinux=0 noacpi maxcpus=1"
Kconfig options :
CONFIG_CRASH_DUMP=y
CONFIG_PHYSICAL_START=0x200000
CONFIG_RELOCATABLE=y
CONFIG_PHYSICAL_ALIGN=0x200000
Please suggest.
Chandan
Dave Anderson <anderson at redhat.com>
Sent by: crash-utility-bounces at redhat.com
08/12/2009 07:39 PM
Please respond to
"Discussion list for crash utility usage, maintenance and
development" <crash-utility at redhat.com>
To
"Discussion list for crash utility usage, maintenance and
development" <crash-utility at redhat.com>
cc
Subject
Re: [Crash-utility] vmcore file size 0 on x86_64
Forwarded to kexec list:
http://lists.infradead.org/pipermail/kexec/2009-August/003474.html
----- "Chandan12 K" <chandan12.k at tcs.com> wrote:
> Hi,
>
> I am little new in this mailing list. I just wondered if anybody could
> help me regarding the vmcore file generation. I ran kexec on my x86_64
> machine, and the /proc/vmcore file is created with zero size.
>
> However, even if I read the /dev/oldmem file, I am only able to read
> till 16M. I guess I am only able to read till the 'X', where X is
> crashkernel=Y at X.
>
> Moreover, My machine seems to have 32 bit user space and ofcourse, 64
> bit kernel space.
>
> Appreciate any response.
>
> Chandan Kumar
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