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 <[email protected]> --- drivers/of/fdt.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index d1ffca8b34ea..3b423f5b99c6 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -930,6 +930,11 @@ 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); } -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
