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Patch "x86/setup: Fix low identity map for >= 2GB kernel range" has been added to the 3.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 7, 2015

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This is a note to let you know that I've just added the patch titled

x86/setup: Fix low identity map for >= 2GB kernel range

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-setup-fix-low-identity-map-for-2gb-kernel-range.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 68accac392d859d24adcf1be3a90e41f978bd54c Mon Sep 17 00:00:00 2001

From: Krzysztof Mazur <[email protected]>
Date: Fri, 6 Nov 2015 14:18:36 +0100
Subject: x86/setup: Fix low identity map for >= 2GB kernel range

From: Krzysztof Mazur <[email protected]>

commit 68accac392d859d24adcf1be3a90e41f978bd54c upstream.

The commit f5f3497cad8c extended the low identity mapping. However, if the kernel uses more than 2 GB (VMSPLIT_2G_OPT or VMSPLIT_1G memory split), the normal memory mapping is overwritten by the low identity mapping causing a crash. To avoid overwritting, limit the low identity map to cover only memory before kernel range (PAGE_OFFSET).

Fixes f5f3497cad8c "x86/setup: Extend low identity map to cover whole kernel range
Cc Andy Lutomirski <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Laszlo Ersek <[email protected]>
Cc Matt Fleming <[email protected]>
Cc Paolo Bonzini <[email protected]>
---
 arch/x86/kernel/setup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/setup.c +1 -1
@@ -1185,7 +1185,7 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	clone_pgd_range(initial_page_table,
 			swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
-			KERNEL_PGD_PTRS);
+			min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
 #endif
 
 	tboot_probe();

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/x86-setup-fix-low-identity-map-for-2gb-kernel-range.patch