Linux doesn't create /proc/vmcore

[matt stuart]

Why doesn't linux create /proc/vmcore while kernel conf marked as does?

my running kernel configuration:
CONFIG_DEBUG_INFO=y
CONFIG_KEXEC=y
CONFIG_CRASH_DUMP=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_PROC_VMCORE=y

my error on the kdump:
kdump-config savecore
running makedumpfile -c -d 31 /proc/vmcore
/var/crash/201305180259/dump-incomplete.
open_dump_memory: Can't open the dump memory(/proc/vmcore). No such
file or directory

makedumpfile Failed.
kdump-config: makedumpfile failed, falling back to 'cp' ... failed!
cp: cannot stat `/proc/vmcore': No such file or directory
kdump-config: failed to save vmcore in /var/crash/201305180259 ... failed!
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[Atsushi Kumagai]

Hello matt,

> CONFIG_PROC_VMCORE=y

Is it specified for the capture kernel ?
By any chance, did you run kdump-config on the system kernel,
not on the capture kernel ?

> DESCRIPTION
> kdump-config manages the kdump feature of the Linux kernel. When a
> kdump enabled kernel panics, it immediately boots into a clean kernel
> called the kdump kernel. The memory image of the panicked kernel will
> be presented in /proc/vmcore while the kdump kernel (or "capture
> kernel") is running.

/proc/vmcore doesn't be created on the system kernel, this tool should be
run on the capture kernel.

And this document may help you:

Documentation/kdump/kdump.txt


Thanks
Atsushi Kumagai