From f014a556e714dfb02502e3be6146a39ca625f33c Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Sun, 30 Oct 2005 14:59:37 -0800 Subject: [PATCH] [PATCH] fixup bogus e820 entry with mem= 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/setup.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index 9b8c8a19824d..b48ac635f3c1 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -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; } } -- 2.20.1