Bug 705636 - MTRR logic makes 90% of RAM inaccessible
Summary: MTRR logic makes 90% of RAM inaccessible
Keywords:
Status: CLOSED DUPLICATE of bug 662238
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.1
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: rc
: ---
Assignee: Prarit Bhargava
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-05-17 23:47 UTC by Philip Pokorny
Modified: 2018-11-14 12:31 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-05-20 14:28:03 UTC
Target Upstream Version:

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Description Philip Pokorny 2011-05-17 23:47:23 UTC 
Description of problem:

Booting 2.6.32-122 kernel on an AMD system gives this message:

WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 29184MB of RAM.
------------[ cut here ]------------
WARNING: at arch/x86/kernel/cpu/mtrr/cleanup.c:1092 mtrr_trim_uncached_memory+0xx
2de/0x309() (Not tainted)
Hardware name: empty
Modules linked in:
Pid: 0, comm: swapper Not tainted 2.6.32-122.el6.x86_64 #1
Call Trace:
 [<ffffffff81066ee7>] ? warn_slowpath_common+0x87/0xc0
 [<ffffffff81066f3a>] ? warn_slowpath_null+0x1a/0x20
 [<ffffffff81bc9288>] ? mtrr_trim_uncached_memory+0x2de/0x309
 [<ffffffff81bc30f2>] ? setup_arch+0x4c4/0xacb
 [<ffffffff814d8ea5>] ? printk+0x41/0x44
 [<ffffffff81bbdbe7>] ? start_kernel+0xdc/0x424
 [<ffffffff81bbd33a>] ? x86_64_start_reservations+0x125/0x129
 [<ffffffff81bbd438>] ? x86_64_start_kernel+0xfa/0x109
---[ end trace a7919e7f17c0a725 ]---

This is a system with a newer AMD processor and the fix is available upstream in 3fdbf004c1706480a7c7fac3c9d836fa6df20d7d


Version-Release number of selected component (if applicable):

2.6.32-122

How reproducible:

100% Multiple systems with Interlagos CPU's

Steps to Reproduce:
1. Boot kernel
2. dmesg
3. free
  
Actual results:

Kernel BUG
no memory

Expected results:

No bug
All memory available.

Additional info:
Comment 1 Philip Pokorny 2011-05-17 23:48:57 UTC 
I am told this was fixed in kernel 2.6.32-130, but I don't see that Red Hat Beta has any accessible repository (RHN, Yum, etc.) where I can download updated kernels.

Please provide a link to the latest Red Hat Beta kernel after 2.6.32-130 so that I can continue testing the Beta on this new hardware.

Thanks,
Phil P.
Comment 3 Prarit Bhargava 2011-05-20 14:28:03 UTC 
Philip, RHEL6.1 has just been released and should resolve your problem.  Please reply back if RHEL6.1 does not fix your problem and reopen this BZ.

Thanks,

P.

*** This bug has been marked as a duplicate of bug 662238 ***
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