Given large enough allocations and a machine with low enough memory (i.e
a default QEMU VM), it's entirely possible that
kmsan_init_alloc_meta_for_range's shadow+origin allocation fails.
Instead of eating a NULL deref kernel oops, check explicitly for memblock_alloc()
failure and panic with a nice error message.
Signed-off-by: Pedro Falcato <pedro.falcato@xxxxxxxxx>
---
mm/kmsan/shadow.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c
index 87318f9170f..3dae3d9c0b3 100644
--- a/mm/kmsan/shadow.c
+++ b/mm/kmsan/shadow.c
@@ -285,12 +285,18 @@ void __init kmsan_init_alloc_meta_for_range(void *start, void *end)
size = PAGE_ALIGN((u64)end - (u64)start);
shadow = memblock_alloc(size, PAGE_SIZE);
origin = memblock_alloc(size, PAGE_SIZE);
+
+ if (!shadow || !origin)
+ panic("%s: Failed to allocate metadata memory for early boot range "
+ "of size %llu",
+ __func__, size);
+
for (u64 addr = 0; addr < size; addr += PAGE_SIZE) {
page = virt_to_page_or_null((char *)start + addr);
- shadow_p = virt_to_page_or_null((char *)shadow + addr);
+ shadow_p = virt_to_page((char *)shadow + addr);
set_no_shadow_origin_page(shadow_p);
shadow_page_for(page) = shadow_p;
- origin_p = virt_to_page_or_null((char *)origin + addr);
+ origin_p = virt_to_page((char *)origin + addr);
set_no_shadow_origin_page(origin_p);
origin_page_for(page) = origin_p;
}
--
2.42.0
