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[PATCH] fixup bogus e820 entry with mem=

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This was reported because someone was getting oopses reading /proc/iomem.
It was tracked down to a zero-sized 'struct resource' entry which was
located right at 4GB.

You need two conditions to hit this bug: a BIOS E820_RAM area starting at
exactly the boundary where you specify mem= (to get a zero-sized entry),
and for the legacy_init_iomem_resources() loop to skip that resource (which
only happens at exactly 4G).

I think the killing zero-sized e820 entry is the easiest way to fix this.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dave Hansen 2005-10-30 14:59:37 -08:00 committed by Linus Torvalds
parent 750deaa402
commit f014a556e7
1 changed files with 17 additions and 7 deletions
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24
arch/i386/kernel/setup.c
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@ -389,14 +389,24 @@ static void __init limit_regions(unsigned long long size)
}
}
for (i = 0; i < e820.nr_map; i++) {
if (e820.map[i].type == E820_RAM) {
current_addr = e820.map[i].addr + e820.map[i].size;
if (current_addr >= size) {
e820.map[i].size -= current_addr-size;
e820.nr_map = i + 1;
return;
}
current_addr = e820.map[i].addr + e820.map[i].size;
if (current_addr < size)
continue;
if (e820.map[i].type != E820_RAM)
continue;
if (e820.map[i].addr >= size) {
/*
* This region starts past the end of the
* requested size, skip it completely.
*/
e820.nr_map = i;
} else {
e820.nr_map = i + 1;
e820.map[i].size -= current_addr - size;
}
return;
}
}