GitLab

Commit b10d6bca ("arch, drivers: replace for_each_membock() with
for_each_mem_range()") didn't take into account that when there is
movable_node parameter in the kernel command line, for_each_mem_range()
would skip ranges marked with MEMBLOCK_HOTPLUG.

The page table setup code in POWER uses for_each_mem_range() to create
the linear mapping of the physical memory and since the regions marked
as MEMORY_HOTPLUG are skipped, they never make it to the linear map.

A later access to the memory in those ranges will fail:

  BUG: Unable to handle kernel data access on write at 0xc000000400000000
  Faulting instruction address: 0xc00000000008a3c0
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 0 PID: 53 Comm: kworker/u2:0 Not tainted 5.13.0 #7
  NIP:  c00000000008a3c0 LR: c0000000003c1ed8 CTR: 0000000000000040
  REGS: c000000008a57770 TRAP: 0300   Not tai...