On 2020/10/6 1:16, Catalin Marinas wrote:

On Mon, Sep 07, 2020 at 09:47:42PM +0800, Chen Zhou wrote:

quoted

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 53acbeca4f57..1b24072f2bae 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c

@@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 #ifdef CONFIG_KEXEC_CORE
-		/* Userspace will find "Crash kernel" region in /proc/iomem. */
+		/*
+		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
+		 * region in /proc/iomem.
+		 * In order to distinct from the high region and make no effect
+		 * to the use of existing kexec-tools, rename the low region as
+		 * "Crash kernel (low)".
+		 */
+		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
+				crashk_low_res.end <= res->end) {
+			crashk_low_res.name = "Crash kernel (low)";
+			request_resource(res, &crashk_low_res);
+		}

With the changes in this series (including the above), how do the
current kexec-tools behave? Do they pick just the high region and the
loaded kernel will subsequently fail to boot?

Yes，just pick the high region and will boot fail if low memory is needed.

Thanks,
Chen Zhou