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x86/ldt: Correct LDT access in single stepping logic

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Commit 37868fe113 ("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: 37868fe113: 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>
This commit is contained in:
Juergen Gross 2015-08-06 10:04:38 +02:00 committed by Ingo Molnar
parent dd2384a75d
commit 136d9d83c0
1 changed files with 2 additions and 2 deletions
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4
arch/x86/kernel/step.c
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@ -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];