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>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index ef2c3563357d..006281302925 100644
--- 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)