Re: [Bugme-new] [Bug 11490] New: Old mtrr bug comeback

[Yinghai Lu]

On Wed, Sep 3, 2008 at 9:18 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Wed,  3 Sep 2008 08:44:27 -0700 (PDT) bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote:
>
>> http://bugzilla.kernel.org/show_bug.cgi?id=11490
>>
>>            Summary: Old mtrr bug comeback
>>            Product: Memory Management
>>            Version: 2.5
>>      KernelVersion: v2.6.27-rc5
>>           Platform: All
>>         OS/Version: Linux
>>               Tree: Mainline
>>             Status: NEW
>>           Severity: normal
>>           Priority: P1
>>          Component: MTTR
>>         AssignedTo: akpm@xxxxxxxx
>>         ReportedBy: ak@xxxxxxx
>>
>>
>> Latest working kernel version:v2.6.26.3
>>
>> Old mtrr bug comeback, when i boot my notebook with last kerenl they going to
>> work really slow as turttle. to boot on normal speed i need use kernel param
>> mem=1000M
>>
>> when i use 2.6.26.3 everyting going fine. as i remember that bug fixed in
>> 2.6.26 stable release and was in 2.6.25 and earlier.
>>
>> probably you can find more details in bugzilla.redhat.com or
>> bugzilla.mozilla.com i do no remember where is exactly i have been posted that
>> old bug.
>>
>> here the point (warning on 2.6.26.3 kernel):
>>
>> WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 7MB of RAM.
>> ------------[ cut here ]------------
>> WARNING: at arch/x86/kernel/cpu/mtrr/main.c:706
>> mtrr_trim_uncached_memory+0x103/0x168()
>> Modules linked in:
>> Pid: 0, comm: swapper Not tainted 2.6.26.3 #1
>>  [<c06260e9>] ? printk+0xf/0x16
>>  [<c0427749>] warn_on_slowpath+0x41/0x7b
>>  [<c0628171>] ? _spin_unlock_irqrestore+0x10/0x14
>>  [<c0628171>] ? _spin_unlock_irqrestore+0x10/0x14
>>  [<c0427e4f>] ? release_console_sem+0x181/0x189
>>  [<c04282d3>] ? vprintk+0x2e6/0x30b
>>  [<c04282d3>] ? vprintk+0x2e6/0x30b
>>  [<c040dbfd>] ? generic_get_mtrr+0x53/0x8a
>>  [<c0756177>] mtrr_trim_uncached_memory+0x103/0x168
>>  [<c075606c>] ? mtrr_bp_init+0x204/0x20c
>>  [<c07539a9>] setup_arch+0x27b/0x6ce
>>  [<c06260e9>] ? printk+0xf/0x16
>>  [<c074d5c0>] start_kernel+0x64/0x2da
>>  [<c074d008>] __init_begin+0x8/0xa
>>  =======================
>> ---[ end trace 4eaa2a86a8e2da22 ]---
>> update e820 for mtrr
>> modified physical RAM map:
>>
>
> A post-2.6.26 regression.
>
> We have a couple of mtrr fixes pending:
>
> http://userweb.kernel.org/~akpm/mmotm/broken-out/x86-delay-early-cpu-initialization-until-cpuid-is-done.patch
>
> http://userweb.kernel.org/~akpm/mmotm/broken-out/x86-move-mtrr-cpu-cap-setting-early-in-early_init_xxxx.patch
>
> but I don't know if they'll fix this regression?
>

cpu?

dmesg  with debug and initcall_debug

cat /proc/mtrr

YH
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/