Patch "x86/ldt: Correct LDT access in single stepping logic" has been added to the 4.1-stable tree

Patch "x86/ldt: Correct LDT access in single stepping logic" has been added to the 4.1-stable tree

[gregkh]

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

    x86/ldt: Correct LDT access in single stepping logic

to the 4.1-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-ldt-correct-ldt-access-in-single-stepping-logic.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 136d9d83c07c5e30ac49fc83b27e8c4842f108fc Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Thu, 6 Aug 2015 10:04:38 +0200
Subject: x86/ldt: Correct LDT access in single stepping logic

From: Juergen Gross <jgross@suse.com>

commit 136d9d83c07c5e30ac49fc83b27e8c4842f108fc upstream.

Commit 37868fe113ff ("x86/ldt: Make modify_ldt synchronous")
introduced a new struct ldt_struct anchored at mm->context.ldt.

convert_ip_to_linear() was changed to reflect this, but indexing
into the ldt has to be changed as the pointer is no longer void *.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@suse.de
Link: http://lkml.kernel.org/r/1438848278-12906-1-git-send-email-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/step.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -28,11 +28,11 @@ unsigned long convert_ip_to_linear(struc
 		struct desc_struct *desc;
 		unsigned long base;
 
-		seg &= ~7UL;
+		seg >>= 3;
 
 		mutex_lock(&child->mm->context.lock);
 		if (unlikely(!child->mm->context.ldt ||
-			     (seg >> 3) >= child->mm->context.ldt->size))
+			     seg >= child->mm->context.ldt->size))
 			addr = -1L; /* bogus selector, access would fault */
 		else {
 			desc = &child->mm->context.ldt->entries[seg];


Patches currently in stable-queue which might be from jgross@suse.com are

queue-4.1/x86-ldt-correct-ldt-access-in-single-stepping-logic.patch
queue-4.1/x86-ldt-correct-fpu-emulation-access-to-ldt.patch
queue-4.1/x86-ldt-further-fix-fpu-emulation.patch