From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yinghai Lu <yinghai@kernel.org>
Subject: [PATCH -v8] x86: Do not free zero sized per cpu areas
Date: Fri, 26 Mar 2010 18:18:20 -0700
Message-ID: <4BAD5CDC.5080308@kernel.org>
References: <1269642114-16588-1-git-send-email-yinghai@kernel.org> <1269642114-16588-4-git-send-email-yinghai@kernel.org>
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To: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>, Andrew Morton <akpm@linux-foundation.org>, David Miller <davem@davemloft.net>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Linus Torvalds <torvalds@linux-foundation.org>, Johannes Weiner <hannes@cmpxchg.org>, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Ian Campbell <ian.campbell@citrix.com>, Peter Zijlstra <peterz@infradead.org>


From: Ian Campbell <ian.campbell@citrix.com>

This avoids an infinite loop in free_early_partial().

Add a warning to free_early_partial to catch future problems.

-v5: put back start > end back into WARN_ONCE()
-v6: use one line for warning according to linus
-v7: more test by
-v8: remove the function name according to Johannes
     WARN_ONCE will print that function name.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Joel Becker <joel.becker@oracle.com>
Tested-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
---
 kernel/early_res.c |    6 ++++++
 1 file changed, 6 insertions(+)

Index: linux-2.6/kernel/early_res.c
===================================================================
--- linux-2.6.orig/kernel/early_res.c
+++ linux-2.6/kernel/early_res.c
@@ -333,6 +333,12 @@ void __init free_early_partial(u64 start
 	struct early_res *r;
 	int i;
 
+	if (start == end)
+		return;
+
+	if (WARN_ONCE(start > end, "  wrong range [%#llx, %#llx]\n", start, end))
+		return;
+
 try_next:
 	i = find_overlapped_early(start, end);
 	if (i >= max_early_res)