linux-kernel - [patch 16/21] x86, ds: add leakage warning

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Date:	Tue, 31 Mar 2009 15:36:18 +0200
From:	Markus Metzger <markus.t.metzger@...el.com>
To:	linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de,
	hpa@...or.com
Cc:	markus.t.metzger@...el.com, markus.t.metzger@...il.com,
	roland@...hat.com, eranian@...glemail.com, oleg@...hat.com,
	juan.villacis@...el.com, ak@...ux.jf.intel.com
Subject: [patch 16/21] x86, ds: add leakage warning

Add a warning in case a debug store context is not removed before
the task it is attached to is freed.

Remove the old warning at thread exit. It is too early for deferred
branch trace stopping.


Signed-off-by: Markus Metzger <markus.t.metzger@...el.com>
---

Index: git-tip/arch/x86/kernel/ds.c
===================================================================
--- git-tip.orig/arch/x86/kernel/ds.c	2009-03-31 08:36:18.000000000 +0200
+++ git-tip/arch/x86/kernel/ds.c	2009-03-31 08:37:29.000000000 +0200
@@ -1383,10 +1383,6 @@ void ds_copy_thread(struct task_struct *
 	tsk->thread.ds_ctx = NULL;
 }
 
-void ds_exit_thread(struct task_struct *tsk)
-{
-}
-
 static __init int ds_selftest(void)
 {
 	if (ds_cfg.sizeof_rec[ds_bts]) {
Index: git-tip/arch/x86/include/asm/ds.h
===================================================================
--- git-tip.orig/arch/x86/include/asm/ds.h	2009-03-31 08:36:18.000000000 +0200
+++ git-tip/arch/x86/include/asm/ds.h	2009-03-31 08:37:27.000000000 +0200
@@ -289,7 +289,6 @@ extern void ds_switch_to(struct task_str
  * Task clone/init and cleanup work
  */
 extern void ds_copy_thread(struct task_struct *tsk, struct task_struct *father);
-extern void ds_exit_thread(struct task_struct *tsk);
 
 #else /* CONFIG_X86_DS */
 
@@ -299,7 +298,6 @@ static inline void ds_switch_to(struct t
 				struct task_struct *next) {}
 static inline void ds_copy_thread(struct task_struct *tsk,
 				  struct task_struct *father) {}
-static inline void ds_exit_thread(struct task_struct *tsk) {}
 
 #endif /* CONFIG_X86_DS */
 #endif /* _ASM_X86_DS_H */
Index: git-tip/arch/x86/kernel/process.c
===================================================================
--- git-tip.orig/arch/x86/kernel/process.c	2009-03-31 08:36:18.000000000 +0200
+++ git-tip/arch/x86/kernel/process.c	2009-03-31 08:38:07.000000000 +0200
@@ -45,6 +45,8 @@ void free_thread_xstate(struct task_stru
 		kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
 		tsk->thread.xstate = NULL;
 	}
+
+	WARN(tsk->thread.ds_ctx, "leaking DS context\n");
 }
 
 void free_thread_info(struct thread_info *ti)
@@ -82,8 +84,6 @@ void exit_thread(void)
 		t->io_bitmap_max = 0;
 		put_cpu();
 	}
-
-	ds_exit_thread(current);
 }
 
 void flush_thread(void)
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