Commit 136d9d83 authored Aug 06, 2015 by Juergen Gross Committed by Ingo Molnar Aug 08, 2015

x86/ldt: Correct LDT access in single stepping logic



Commit 37868fe1 ("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: <stable@vger.kernel.org> # On top of: 37868fe1: x86/ldt: Make modify_ldt synchronous
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>

parent dd2384a7

arch/x86/kernel/step.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -28,11 +28,11 @@ unsigned long convert_ip_to_linear(struct task_struct child, struct pt_regs re
		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];