From: Prarit Bhargava <prarit@redhat.com>
To: linux-kernel@vger.kernel.org, dzickus@redhat.com,
nhorman@redhat.com, vgoyal@redhat.com
Cc: Prarit Bhargava <prarit@redhat.com>
Subject: [PATCH] Fix memmap=exactmap boot argument
Date: Tue, 9 Sep 2008 09:56:08 -0400 [thread overview]
Message-ID: <20080909134858.20868.51265.sendpatchset@prarit.bos.redhat.com> (raw)
When using kdump modifying the e820 map is yielding strange results.
For example starting with
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000100 - 0000000000093400 (usable)
BIOS-e820: 0000000000093400 - 00000000000a0000 (reserved)
BIOS-e820: 0000000000100000 - 000000003fee0000 (usable)
BIOS-e820: 000000003fee0000 - 000000003fef3000 (ACPI data)
BIOS-e820: 000000003fef3000 - 000000003ff80000 (ACPI NVS)
BIOS-e820: 000000003ff80000 - 0000000040000000 (reserved)
BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
and booting with args
memmap=exactmap memmap=640K@0K memmap=5228K@16384K memmap=125188K@22252K memmap=76K#1047424K memmap=564K#1047500K
resulted in:
user-defined physical RAM map:
user: 0000000000000000 - 0000000000093400 (usable)
user: 0000000000093400 - 00000000000a0000 (reserved)
user: 0000000000100000 - 000000003fee0000 (usable)
user: 000000003fee0000 - 000000003fef3000 (ACPI data)
user: 000000003fef3000 - 000000003ff80000 (ACPI NVS)
user: 000000003ff80000 - 0000000040000000 (reserved)
user: 00000000e0000000 - 00000000f0000000 (reserved)
user: 00000000fec00000 - 00000000fec10000 (reserved)
user: 00000000fee00000 - 00000000fee01000 (reserved)
user: 00000000ff000000 - 0000000100000000 (reserved)
But should have resulted in:
user-defined physical RAM map:
user: 0000000000000000 - 00000000000a0000 (usable)
user: 0000000001000000 - 000000000151b000 (usable)
user: 00000000015bb000 - 0000000008ffc000 (usable)
user: 000000003fee0000 - 000000003ff80000 (ACPI data)
This is happening because of an improper usage of strcmp() in the
e820 parsing code. The strcmp() always returns !0 and never resets the
value for e820.nr_map and returns an incorrect user-defined map.
This patch fixes the problem.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 9af8907..66e48aa 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1203,7 +1203,7 @@ static int __init parse_memmap_opt(char *p)
if (!p)
return -EINVAL;
- if (!strcmp(p, "exactmap")) {
+ if (!strncmp(p, "exactmap", 8)) {
#ifdef CONFIG_CRASH_DUMP
/*
* If we are doing a crash dump, we still need to know
next reply other threads:[~2008-09-09 13:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-09 13:56 Prarit Bhargava [this message]
2008-09-09 14:37 ` Ingo Molnar
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