Re: warning in arch/x86/kernel/cpu/mtrr/generic.c:400 with 2.6.29-rc3 on IBM x3400

[Yinghai Lu <yinghai@kernel.org>]

Morten P.D. Stevens wrote:
> Hi,
> 
>> so that bios need to be fixed too.
> 
> a small update:
> IBM said the BIOS-provided physical RAM map should be okay and they will not
> release a new bios... IBM said, this is a linux problem triggered through
> arch/x86/kernel/cpu/mtrr/...
> 
> After installing and testing ubuntu server 9.04 (linux 2.6.28) i get this
> warning/failure in dmesg:
> 
> [    0.000000] BIOS EBDA/lowmem at: 0009c400/0009c400
> [    0.000000] Initializing cgroup subsys cpuset
> [    0.000000] Initializing cgroup subsys cpu
> [    0.000000] Linux version 2.6.28-11-server (buildd@crested) (gcc version
> 4.3.3 (Ubuntu 4.3.3-5ubuntu4) ) #37-Ubuntu SMP Mon Mar 23 17:33:24 UTC 2009
> (Ubuntu 2.6.28-11.37-server)
> [    0.000000] Command line: root=/dev/mapper/ubuntu--server-root ro quiet
> splash 
> [    0.000000] KERNEL supported cpus:
> [    0.000000]   Intel GenuineIntel
> [    0.000000]   AMD AuthenticAMD
> [    0.000000]   Centaur CentaurHauls
> [    0.000000] BIOS-provided physical RAM map:
> [    0.000000]  BIOS-e820: 0000000000000000 - 000000000009c400 (usable)
> [    0.000000]  BIOS-e820: 000000000009c400 - 00000000000a0000 (reserved)
> [    0.000000]  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
> [    0.000000]  BIOS-e820: 0000000000100000 - 00000000bff60000 (usable)
> [    0.000000]  BIOS-e820: 00000000bff60000 - 00000000bff6a000 (ACPI data)
> [    0.000000]  BIOS-e820: 00000000bff6a000 - 00000000bff80000 (ACPI NVS)
> [    0.000000]  BIOS-e820: 00000000bff80000 - 00000000c0000000 (reserved)
> [    0.000000]  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
> [    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
> [    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
> [    0.000000]  BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
> [    0.000000]  BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
> [    0.000000] DMI present.
> [    0.000000] last_pfn = 0x140000 max_arch_pfn = 0x3ffffffff
> [    0.000000] ------------[ cut here ]------------
> [    0.000000] WARNING: at
> /build/buildd/linux-2.6.28/arch/x86/kernel/cpu/mtrr/generic.c:411
> generic_get_mtrr+0xfa/0x130()
> [    0.000000] mtrr: your BIOS has set up an incorrect mask, fixing it up.
> [    0.000000] Modules linked in:
> [    0.000000] Pid: 0, comm: swapper Not tainted 2.6.28-11-server #37-Ubuntu
> [    0.000000] Call Trace:
> [    0.000000]  [<ffffffff80250927>] warn_slowpath+0xb7/0xf0
> [    0.000000]  [<ffffffff8041ea88>] ? sprintf+0x68/0x70
> [    0.000000]  [<ffffffff8041e5d8>] ? vsnprintf+0x2e8/0x730
> [    0.000000]  [<ffffffff8069eaf8>] ? _spin_unlock_irqrestore+0x18/0x20
> [    0.000000]  [<ffffffff8069eaf8>] ? _spin_unlock_irqrestore+0x18/0x20
> [    0.000000]  [<ffffffff8025124d>] ? release_console_sem+0x1dd/0x230
> [    0.000000]  [<ffffffff8025172c>] ? vprintk+0x19c/0x400
> [    0.000000]  [<ffffffff80a1aa16>] ? dmi_save_one_device+0x79/0xb4
> [    0.000000]  [<ffffffff80220c6a>] generic_get_mtrr+0xfa/0x130
> [    0.000000]  [<ffffffff809f7215>] mtrr_trim_uncached_memory+0xa3/0x331
> [    0.000000]  [<ffffffff809f26c4>] setup_arch+0x5c6/0x902
> [    0.000000]  [<ffffffff80273822>] ?
> clockevents_register_notifier+0x42/0x60
> [    0.000000]  [<ffffffff809e9b33>] start_kernel+0x6e/0x3b2
> [    0.000000]  [<ffffffff809e92b4>] x86_64_start_reservations+0x94/0xb9
> [    0.000000]  [<ffffffff809e93ee>] x86_64_start_kernel+0xf2/0x101
> [    0.000000]  [<ffffffff809e9140>] ? early_idt_handler+0x0/0x71
> [    0.000000] ---[ end trace 4eaa2a86a8e2da22 ]---
> [    0.000000] last_pfn = 0xbff60 max_arch_pfn = 0x3ffffffff
> [    0.000000] Scanning 2 areas for low memory corruption
> [    0.000000] modified physical RAM map:
> [    0.000000]  modified: 0000000000000000 - 0000000000001000 (usable)
> [    0.000000]  modified: 0000000000001000 - 0000000000006000 (reserved)
> [    0.000000]  modified: 0000000000006000 - 0000000000008000 (usable)
> [    0.000000]  modified: 0000000000008000 - 0000000000010000 (reserved)
> [    0.000000]  modified: 0000000000010000 - 000000000008f400 (usable)
> [    0.000000]  modified: 000000000009c400 - 00000000000a0000 (reserved)
> [    0.000000]  modified: 00000000000e0000 - 0000000000100000 (reserved)
> [    0.000000]  modified: 0000000000100000 - 00000000bff60000 (usable)
> [    0.000000]  modified: 00000000bff60000 - 00000000bff6a000 (ACPI data)
> [    0.000000]  modified: 00000000bff6a000 - 00000000bff80000 (ACPI NVS)
> [    0.000000]  modified: 00000000bff80000 - 00000000c0000000 (reserved)
> [    0.000000]  modified: 00000000e0000000 - 00000000f0000000 (reserved)
> [    0.000000]  modified: 00000000fec00000 - 00000000fec10000 (reserved)
> [    0.000000]  modified: 00000000fee00000 - 00000000fee01000 (reserved)
> [    0.000000]  modified: 00000000ff000000 - 0000000100000000 (reserved)
> [    0.000000]  modified: 0000000100000000 - 0000000140000000 (usable)
> [    0.000000] init_memory_mapping: 0000000000000000-00000000bff60000
> [    0.000000]  0000000000 - 00bfe00000 page 2M
> [    0.000000]  00bfe00000 - 00bff60000 page 4k
> [    0.000000] kernel direct mapping tables up to bff60000 @ 10000-15000
> [    0.000000] last_map_addr: bff60000 end: bff60000
> [    0.000000] init_memory_mapping: 0000000100000000-0000000140000000
> [    0.000000]  0100000000 - 0140000000 page 2M
> [    0.000000] kernel direct mapping tables up to 140000000 @ 13000-19000
> [    0.000000] last_map_addr: 140000000 end: 140000000
> 
> root@ubuntu-server:/# uname -a
> Linux ubuntu-server 2.6.28-11-server #37-Ubuntu SMP Mon Mar 23 17:33:24 UTC
> 2009 x86_64 GNU/Linux
> 
> root@ubuntu-server:/# cat /proc/mtrr
> reg00: base=0x0c0000000 ( 3072MB), size= 1024MB, count=1: uncachable
> reg01: base=0x000000000 (    0MB), size= 4096MB, count=1: write-back
> reg02: base=0x100000000 ( 4096MB), size= 1024MB, count=1: write-back
> reg03: base=0x0bff80000 ( 3071MB), size=  512KB, count=1: uncachable

that mean new kernel workaround the mask bits.

you can try to set
CONFIG_MTRR=y
CONFIG_MTRR_SANITIZER=y
CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT=1
CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT=1
in your config
it could make your Xserver happy.

YH