tree c513abe365abe3c849e1339b58479f4dc143d068
parent 15541e64163c0c5a2d2e3e8d1b73057888170f62
author Baoquan He <bhe@redhat.com> 1498567146 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1499258429 +0200

x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug

commit 8eabf42ae5237e6b699aeac687b5b629e3537c8d upstream.

Kernel text KASLR is separated into physical address and virtual
address randomization. And for virtual address randomization, we
only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE.
So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR,
but not the original kernel loading address 'output'.

The bug will cause kernel boot failure if kernel is loaded at a different
position than the address, 16M, which is decided at compiled time.
Kexec/kdump is such practical case.

To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial
value.

Tested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately")
Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>