[04/78] x86: Fix panic when handling "mem={invalid}" param

From: Greg KH
Date: Mon Mar 21 2011 - 19:32:57 EST

2.6.38-stable review patch. If anyone has any objections, please let us know.


From: Kamal Mostafa <kamal@xxxxxxxxxxxxx>

commit 77eed821accf5dd962b1f13bed0680e217e49112 upstream.

Avoid removing all of memory and panicing when "mem={invalid}"
is specified, e.g. mem=blahblah, mem=0, or mem=nopentium (on
platforms other than x86_32).

Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
BugLink: http://bugs.launchpad.net/bugs/553464
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
LKML-Reference: <1296783486-23033-1-git-send-email-kamal@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

arch/x86/kernel/e820.c | 3 +++
1 file changed, 3 insertions(+)

--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -856,6 +856,9 @@ static int __init parse_memopt(char *p)

userdef = 1;
mem_size = memparse(p, &p);
+ /* don't remove all of memory when handling "mem={invalid}" param */
+ if (mem_size == 0)
+ return -EINVAL;
e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

return 0;

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