From: Robert Hentosh <robert_hentosh@dell.com>
Date: Tue, 30 May 2006 20:48:00 +0000 (+0200)
Subject: [PATCH] x86_64: Fix off by one in bad_addr checking in find_e820_area
X-Git-Tag: v2.6.17-rc6~76
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ca97c6131dac9f06b1856a95a2ec89d43844286;p=pandora-kernel.git

[PATCH] x86_64: Fix off by one in bad_addr checking in find_e820_area

From: Robert Hentosh <robert_hentosh@dell.com>

Actually, we just stumbled on a different bug found in find_e820_area() in
e820.c.  The following code does not handle the edge condition correctly:

   while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
       ;
   last = addr + size;
   if ( last > ei->addr + ei->size )
       continue;

The second statement in the while loop needs to be a <= b so that it is the
logical negavite of the if (a > b) outside it. It needs to read:

   while (bad_addr(&addr, size) && addr+size <= ei->addr + ei->size)
       ;

In the case that failed bad_addr was returning an address that is exactly size
bellow the end of the e820 range.

AK: Again together with the earlier avoid edma fix this fixes
boot on a Dell PE6850/16GB

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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