x86: fix boot hang in early_reserve_e820()

If the first non-reserved (sub-)range doesn't fit the size requested,
an endless loop will be entered. If a range returned from
find_e820_area_size() turns out insufficient in size, the range must
be skipped before calling the function again.

[ Impact: fixes boot hang on some platforms ]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index ef2c3563357d52c6f7d314a1df2cd018bbdca000..0062813029256a2379d4dc66c42741439227210e 100644 (file)
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1074,12 +1074,13 @@ u64 __init early_reserve_e820(u64 startt, u64 sizet, u64 align)
        u64 addr;
        u64 start;
 
-       start = startt;
-       while (size < sizet && (start + 1))
+       for (start = startt; ; start += size) {
                start = find_e820_area_size(start, &size, align);
-
-       if (size < sizet)
-               return 0;
+               if (!(start + 1))
+                       return 0;
+               if (size >= sizet)
+                       break;
+       }
 
 #ifdef CONFIG_X86_32
        if (start >= MAXMEM)