Bug 559 - Passing 'append="mem=128M" ' from LILO to kernel causes kernel panic
Passing 'append="mem=128M" ' from LILO to kernel causes kernel panic
Status: CLOSED WORKSFORME
Product: Red Hat Linux
Classification: Retired
Component: kernel (Show other bugs)
5.2
i386 Linux
medium Severity medium
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Assigned To: David Lawrence
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Reported: 1998-12-22 08:07 EST by anthony_w
Modified: 2008-05-01 11:37 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 1998-12-22 15:48:09 EST
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Description anthony_w 1998-12-22 08:07:20 EST
Affected kernel : 2.0.36

Bug description : When using 'append="mem=128M" ' in
                  'lilo.conf', kernel will panic

Affected system : ASUS P5A Super 7 Mainboard
Disk controller : Adaptec 2940U controller
Hard drives     : IBM 4.3G and Quantum 4.3G
System memory   : 128Mb
CPU             : AMD K6-2 350Mhz

Bug causes "Kernel panic" when passing information on
amount of memory available from LILO to Kernel.

To reproduce bug do the following:

In 'lilo.conf' add this line

	append="mem=128M"

When doing this the following result is reported before
system hangs:

----0000----

Initrd extends beyond end of memory (0x00fff190>0x00000080)
disabling initrd

...some other unrelated messages...

Memory 0K/0K Available (0K kernel code, 0K reserved, 0K
data)
Kernel panic: Failed to allocate buffer hash table

-----0000----

This does not happen if using 'append="mem=96M"' nor does
it happen when using kernel 2.0.34

Bug discovered during upgrade of motherboard memory to
128Mb and not realizing that kernel 2.0.36 should detect
memory > 64Mb automatically.

Removing the 'append' line fixes the problem.  Kernel
should not "zero" out the memory detected when the same
amount is passed from LILO.  It seems that 2 digit
memory numbers do not cause the problem, only 3 digit.

Submitted by Anthony White, Australia

E-Mail:  awhite@c031.aone.net.au  or  anthony_w@bigpond.com
Comment 1 David Lawrence 1998-12-22 15:48:59 EST
I tried this problem on two different ASUS motherboards with 128 megs
of ram withno problem .
Comment 2 Aleksey Nogin 1998-12-23 02:41:59 EST
From BootPrompt-HOWTO :

  ``The kernel will accept any `mem=xx' parameter you give it, and if
it
  turns out that you lied to it, it will crash horribly sooner or
later.

[skipped - AN]

  NOTE NOTE NOTE: some machines might use the top of memory for BIOS
  cacheing or whatever, so you might not actually have up to the full
  xxMB addressable.

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