arm64: pstore: printk causing hang during boot in __memcpy_toio with pstore enabled

[Ivid Suvarna]

Hi,

When pstore is enabled and a *pr_info(any printk) in
__memcpy_toio(arch/arm64/kernel/io.c)* is added, kernel wont boot and
just hangs.

The path where __memcpy_toio is called is below:

->persistent_ram_update
  -> memcpy_toio
    -> __memcpy_toio

I tried with trace_printk and kernel boots fine. I understand that
printk has overhead, but is this expected when we use some printk
statement in __memcpy_toio?

Or is it some kind of bug? Tested on db410c.

Please let me know your opinion.

Thanks,