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@xxxxxxxxxx>
---
v2: use WARN_ON() instead of BUG_ON() [Mel Gorman]
mm/bootmem.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/bootmem.c b/mm/bootmem.c
index a23dd1934654..3b6380784c28 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -236,6 +236,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
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 @@ static void __init __free(bootmem_data_t *bdata,
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 @@ static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
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) {
--
2.1.2
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