issue with kexec/kdump on imx6ull

Russell King - ARM Linux
2018-05-16T10:42:36Z

On Wed, May 16, 2018 at 12:31:20PM +0200, Arthur LAMBERT wrote:
> Le Monday 09 Apr 2018 ? 15:31:23 (+0100), Russell King - ARM Linux a ?crit :
> >
> > > kernel command line: "console=ttymxc0,115200 root=/dev/mmcblk1p2 rootwait rw earlyprintk maxcpus=1 reset_devices elfcorehdr=0x9b100000 mem=50176K"
> >
> > This is the command line which the target kernel should boot with, but...
> >
> > > [ 0.000000] Kernel command line: console=ttymxc0,115200 root=/dev/mmcblk1p2 rootwait rw crashkernel=50M
> >
> > it appears that it hasn't, so something is still wrong. Without the
> > right command line, you won't get the vmcore.
>
> Sorry for my very late answer Russell.
>
> We can see that kexec is able to build the correct command line but instead of booting with this kernel
> command line. Kexec boot the target kernel with default kernel command line.
>
> I am currently forcing kernel command line on my target kernel :
>
> CONFIG_CMDLINE="console=ttymxc0,115200 root=/dev/mmcblk1p2 rootwait rw earlyprintk crashkernel=50M"
> # CONFIG_CMDLINE_FROM_BOOTLOADER is not set
> # CONFIG_CMDLINE_EXTEND is not set
> CONFIG_CMDLINE_FORCE=y

I guess it's taken quite a while to track this down.

I wonder if we should encode that into the zImage, and have kexec print
a friendly error or warning message suggesting the kernel be more
appropriately configured.

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