Capturing crash with 4.6.0 and above kernel does not work

[Himanshu Madhani]

Hello list,

I am wondering if anybody has issue capturing crash dump with the 4.6.0 and above kenrel.

I have a system, when booted in 4.5.7 kernel is able to capture crash dump.
However, when I boot this system in 4.6.4 and 4.7.2 kernel, crash dump is not 
able to capture any crash. 

I am still facing same issue with 4.8.0-rc2+ kernel and from the error at the command prompt, 
it seems like kexec is ignoring âcrashkenrelâ parameter. 

I added below information in https://bugzilla.kernel.org/show_bug.cgi?id=119291. 

# uname -r
4.8.0-rc2+

# cat /proc/cmdline 
ro root=/dev/mapper/vg_dut4110-lv_root rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=us LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=512M rd_LVM_LV=vg_dut4110/lv_swap rd_LVM_LV=vg_dut4110/lv_root rd_NO_DM rhgb quiet

# service kdump status
Kdump is not operational

# service kdump start
Memory for crashkernel is not reserved
Please reserve memory by passing "crashkernel=X@Y" parameter to the kernel
Starting kdump:                                            [FAILED]

message file confirms that kexec was not able to start the service 

Aug 15 10:41:17 dut4110 kdump: kexec: failed to load kdump kernel
Aug 15 10:41:17 dut4110 kdump: failed to start up

Note, that same option is able to load kdump service for 4.5.7 kernel.  

I can provide any details needed to help resolve this issue. 

Thanks,
- Himanshu