bootmem: avoid freeing to bootmem after bootmem is done
Bootmem isn't popular any more, but some architectures still use it, and
freeing to bootmem after calling free_all_bootmem_core() can end up
scribbling over random memory. Instead, make sure the kernel generates
a warning in this case by ensuring the node_bootmem_map field is
non-NULL when are freeing or marking bootmem.
An instance of this bug was just fixed in the tile architecture ("tile:
use free_bootmem_late() for initrd") and catching this case more widely
seems like a good thing.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Paul McQuade <paulmcquad@gmail.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/bootmem.c b/mm/bootmem.c
index a23dd19..3b63807 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -236,6 +236,7 @@
count += pages;
while (pages--)
__free_pages_bootmem(page++, cur++, 0);
+ bdata->node_bootmem_map = NULL;
bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
@@ -294,6 +295,9 @@
sidx + bdata->node_min_pfn,
eidx + bdata->node_min_pfn);
+ if (WARN_ON(bdata->node_bootmem_map == NULL))
+ return;
+
if (bdata->hint_idx > sidx)
bdata->hint_idx = sidx;
@@ -314,6 +318,9 @@
eidx + bdata->node_min_pfn,
flags);
+ if (WARN_ON(bdata->node_bootmem_map == NULL))
+ return 0;
+
for (idx = sidx; idx < eidx; idx++)
if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
if (exclusive) {