[PATCH] disable kaslr in kdump kernel

From: Dave Young
Date: Tue Feb 11 2014 - 05:08:03 EST



KASLR does not work in kdump kernel because it's too early that mem=exactmap
has not been parsed.

Since KASLR does not make much sense for kdump kernel thus let's disable it
for kdump kernel. To check if it is a kdump kernel I just check the cmdline
param elfcorehdr just like is_kdump_kernel.

Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
---
linux-2.6/arch/x86/boot/compressed/aslr.c | 5 +++++
1 file changed, 5 insertions(+)

Index: dyoung/git/linux-2.6/arch/x86/boot/compressed/aslr.c
===================================================================
--- linux-2.6/arch/x86/boot/compressed/aslr.c
+++ linux-2.6/arch/x86/boot/compressed/aslr.c
@@ -293,6 +293,11 @@ unsigned char *choose_kernel_location(un
goto out;
}

+ if (cmdline_find_option("elfcorehdr", NULL, 0) != -1) {
+ debug_putstr("KASLR disabled...\n");
+ goto out;
+ }
+
/* Record the various known unsafe memory ranges. */
mem_avoid_init((unsigned long)input, input_size,
(unsigned long)output, output_size);
--
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