Kdump not working on latest kernels (4.13.0-rc6) ?

[Ritesh Harjani]

Hello,

I tried to check the kdump utility on the latest kernel (4.13-rc6) on ubuntu.
But I could not get it working. Is this functionality broken ?


$  kdump-config show
DUMP_MODE:        kdump
USE_KDUMP:        1
KDUMP_SYSCTL:     kernel.panic_on_oops=1
KDUMP_COREDIR:    /var/crash
crashkernel addr: 0x
current state:    Not ready to kdump

kexec command:
  /sbin/kexec -p --command-line="BOOT_IMAGE=/vmlinuz-4.4.0-87-generic
root=/dev/mapper/vg00-rootvol ro printk.time=1 nomodeset
gfxpayload=text fb=false irqpoll maxcpus=1 nousb"
--initrd=/boot/initrd.img-4.4.0-87-generic
/boot/vmlinuz-4.4.0-87-generic


When I tried kdump-config load. It started giving me below errors :-
"Unknown type (Reserved) while parsing /sys/firmware/memmap/15/type.
Please report this as bug. Using RANGE_RESERVED now."


So based on this thread (https://lkml.org/lkml/2017/3/23/944). I made
below change and tried again.
$ git diff
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 532da61..851364a 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -982,7 +982,7 @@ static const char *__init
e820_type_to_string(struct e820_entry *entry)
        case E820_TYPE_UNUSABLE:        return "Unusable memory";
        case E820_TYPE_PRAM:            return "Persistent Memory (legacy)";
        case E820_TYPE_PMEM:            return "Persistent Memory";
-       case E820_TYPE_RESERVED:        return "Reserved";
+       case E820_TYPE_RESERVED:        return "reserved";
        default:                        return "Unknown E820 type";
        }
 }


With above change, I see below problem :-
$ sudo kdump-config load
ELF core (kcore) parse failed
Cannot load /boot/vmlinuz-4.13.0-rc6+
 * failed to load kdump kernel


Does anyone know what is this issue? Is this broken functionality on
latest kernel. Is there a known fix.
Or am I doing anything wrong ?

PS: my default is 4.4 kernel. I installed 4.13-rc6 kernel on top of that.


Regards
Ritesh