Re: [v2,2/2] powerpc/mm: Ensure "special" zones are empty
flat view
From: Balbir Singh <bsingharora@gmail.com>
Date: 2016-05-11 07:12:03
Also in:
linux-mm
On Tue, 2016-05-10 at 09:55 +1000, Michael Ellerman wrote:
On Thu, 2016-05-05 at 07:54:09 UTC, Oliver O'Halloran wrote:quoted
The mm zone mechanism was traditionally used by arch specific code to partition memory into allocation zones. However there are several zones that are managed by the mm subsystem rather than the architecture. Most architectures set the max PFN of these special zones to zero, however on powerpc we set them to ~0ul. This, in conjunction with a bug in free_area_init_nodes() results in all of system memory being placed in ZONE_DEVICE when enabled. Device memory cannot be used for regular kernel memory allocations so this will cause a kernel panic at boot.This is breaking my freescale machine: Sorting __ex_table... Unable to handle kernel paging request for data at address 0xc000000101e28020 Faulting instruction address: 0xc0000000009ab698 cpu 0x0: Vector: 300 (Data Access) at [c000000000acbb30] pc: c0000000009ab698: .reserve_bootmem_region+0x64/0x8c lr: c0000000009883d0: .free_all_bootmem+0x70/0x200 sp: c000000000acbdb0 msr: 80021000 dar: c000000101e28020 dsisr: 800000 current = 0xc000000000a07640 paca = 0xc00000003fff5000 softe: 0 irq_happened: 0x01 pid = 0, comm = swapper Linux version 4.6.0-rc3-00160-gc09920947f23 (michael@ka1) (gcc version 5.3.0 (GCC) ) #5 SMP Tue May 10 09:44:11 AEST 2016 enter ? for help [link register ] c0000000009883d0 .free_all_bootmem+0x70/0x200 [c000000000acbdb0] c000000000988398 .free_all_bootmem+0x38/0x200 (unreliable) [c000000000acbe80] c00000000097b700 .mem_init+0x5c/0x7c [c000000000acbef0] c000000000971a0c .start_kernel+0x28c/0x4e4 [c000000000acbf90] c000000000000544 start_here_common+0x20/0x5c 0:mon> ? I can give you access some time if you need to debug it.
Could you also please post the bits on the boot containing the zone and node information. That would provide some information about what is broken. Or you could just send the whole dmesg Thanks, Balbir Singh