[PATCH] bootmem: Make ___alloc_bootmem_node_nopanic() to be real nopanic

[PATCH] bootmem: Make ___alloc_bootmem_node_nopanic() to be real nopanic

[Yinghai Lu]

after
| From 99ab7b19440a72ebdf225f99b20f8ef40decee86 Mon Sep 17 00:00:00 2001
| Date: Wed, 11 Jul 2012 14:02:53 -0700
| Subject: [PATCH] mm: sparse: fix usemap allocation above node descriptor
 section

Johannes said:
| while backporting the below patch, I realised that your fix busted
| f5bf18fa22f8 again.  The problem was not a panicking version on
| allocation failure but when the usemap size was too large such that
| goal + size > limit triggers the BUG_ON in the bootmem allocator.  So
| we need a version that passes limit ONLY if the usemap is smaller than
| the section.

after checking the code, the name of ___alloc_bootmem_node_nopanic() does not
reflect the fact.

Make bootmem really not panic.

Hope will kill bootmem sooner.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>    [3.3.x, 3.4.x]

---
 mm/bootmem.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6/mm/bootmem.c
===================================================================
--- linux-2.6.orig/mm/bootmem.c
+++ linux-2.6/mm/bootmem.c
@@ -710,6 +710,10 @@ again:
 	if (ptr)
 		return ptr;
 
+	/* do not panic in alloc_bootmem_bdata() */
+	if (limit && goal + size > limit)
+		limit = 0;
+
 	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
 	if (ptr)
 		return ptr;

--
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[PATCH] bootmem: Make ___alloc_bootmem_node_nopanic() to be real nopanic

[Yinghai Lu]

after
| From 99ab7b19440a72ebdf225f99b20f8ef40decee86 Mon Sep 17 00:00:00 2001
| Date: Wed, 11 Jul 2012 14:02:53 -0700
| Subject: [PATCH] mm: sparse: fix usemap allocation above node descriptor
 section

Johannes said:
| while backporting the below patch, I realised that your fix busted
| f5bf18fa22f8 again.  The problem was not a panicking version on
| allocation failure but when the usemap size was too large such that
| goal + size > limit triggers the BUG_ON in the bootmem allocator.  So
| we need a version that passes limit ONLY if the usemap is smaller than
| the section.

after checking the code, the name of ___alloc_bootmem_node_nopanic() does not
reflect the fact.

Make bootmem really not panic.

Hope will kill bootmem sooner.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: stable@vger.kernel.org

---
 mm/bootmem.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6/mm/bootmem.c
===================================================================
--- linux-2.6.orig/mm/bootmem.c
+++ linux-2.6/mm/bootmem.c
@@ -710,6 +710,10 @@ again:
 	if (ptr)
 		return ptr;
 
+	/* do not panic in alloc_bootmem_bdata() */
+	if (limit && goal + size > limit)
+		limit = 0;
+
 	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
 	if (ptr)
 		return ptr;

--
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