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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-10-29 17:09:32 +0100
committerGrant Likely <grant.likely@linaro.org>2014-11-04 16:43:10 +0000
commit8cccffc52694938fc88f3d90bc7fed8460e27191 (patch)
tree76ea435917e5cfd97859a813103a3aaa52ae5124 /drivers/of/fdt.c
parent50ba08f301a1b0310775deeed00c9b24ba75fe8a (diff)
downloadlinux-8cccffc52694938fc88f3d90bc7fed8460e27191.tar.gz
of: check for size < 0 after rounding in early_init_dt_add_memory_arch
Memory regions passed to early_init_dt_add_memory_arch() are rounded to
PAGE_SIZE by subtracting the size of the leading fractional page from
the 'size' argument. However, size being a u64 type, if its value is
sufficiently small, the subtraction wraps around and produces a bogus
value, potentially leading to crashes.

Fix this by ignoring the memory range in such cases.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Diffstat (limited to 'drivers/of/fdt.c')
-rw-r--r--drivers/of/fdt.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 535124670257..83a8e1154602 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -928,6 +928,11 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 	const u64 phys_offset = __pa(PAGE_OFFSET);
 
 	if (!PAGE_ALIGNED(base)) {
+		if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
+			pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+				base, base + size);
+			return;
+		}
 		size -= PAGE_SIZE - (base & ~PAGE_MASK);
 		base = PAGE_ALIGN(base);
 	}