1 files changed, 21 insertions, 4 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index f8476dfbb60d..5cec8a75a4e8 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -316,6 +316,14 @@ void exit_thread(void)
                 tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
                 put_cpu();
         }
+#ifdef CONFIG_X86_DS
+        /* Free any DS contexts that have not been properly released. */
+        if (unlikely(current->thread.ds_ctx)) {
+                /* we clear debugctl to make sure DS is not used. */
+                update_debugctlmsr(0);
+                ds_free(current->thread.ds_ctx);
+        }
+#endif /* CONFIG_X86_DS */
 }
 
 void flush_thread(void)
@@ -482,18 +490,27 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
 {
         struct thread_struct *prev, *next;
         unsigned long debugctl;
+        unsigned long ds_prev = 0, ds_next = 0;
 
         prev = &prev_p->thread;
         next = &next_p->thread;
 
         debugctl = prev->debugctlmsr;
-        if (next->ds_area_msr != prev->ds_area_msr) {
+
+#ifdef CONFIG_X86_DS
+        if (prev->ds_ctx)
+                ds_prev = (unsigned long)prev->ds_ctx->ds;
+        if (next->ds_ctx)
+                ds_next = (unsigned long)next->ds_ctx->ds;
+
+        if (ds_next != ds_prev) {
                 /* we clear debugctl to make sure DS
                  * is not in use when we change it */
                 debugctl = 0;
                 update_debugctlmsr(0);
-                wrmsr(MSR_IA32_DS_AREA, next->ds_area_msr, 0);
+                wrmsr(MSR_IA32_DS_AREA, ds_next, 0);
         }
+#endif /* CONFIG_X86_DS */
 
         if (next->debugctlmsr != debugctl)
                 update_debugctlmsr(next->debugctlmsr);
@@ -517,13 +534,13 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
                         hard_enable_TSC();
         }
 
-#ifdef X86_BTS
+#ifdef CONFIG_X86_PTRACE_BTS
         if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS))
                 ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS);
 
         if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS))
                 ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES);
-#endif
+#endif /* CONFIG_X86_PTRACE_BTS */
 
 
         if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {