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From: Greg KH <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
	alan@lxorguk.ukuu.org.uk
Subject: [ 03/10] i387: fix sense of sanity check
Date: Thu, 23 Feb 2012 16:02:23 -0800	[thread overview]
Message-ID: <20120224000220.581161542@linuxfoundation.org> (raw)
In-Reply-To: <20120224000510.GA1005@kroah.com>

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torvalds@linux-foundation.org>

commit c38e23456278e967f094b08247ffc3711b1029b2 upstream.

The check for save_init_fpu() (introduced in commit 5b1cbac37798: "i387:
make irq_fpu_usable() tests more robust") was the wrong way around, but
I hadn't noticed, because my "tests" were bogus: the FPU exceptions are
disabled by default, so even doing a divide by zero never actually
triggers this code at all unless you do extra work to enable them.

So if anybody did enable them, they'd get one spurious warning.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/include/asm/i387.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -404,7 +404,7 @@ static inline void irq_ts_restore(int TS
  */
 static inline void save_init_fpu(struct task_struct *tsk)
 {
-	WARN_ON_ONCE(task_thread_info(tsk)->status & TS_USEDFPU);
+	WARN_ON_ONCE(!(task_thread_info(tsk)->status & TS_USEDFPU));
 	preempt_disable();
 	__save_init_fpu(tsk);
 	stts();



  parent reply	other threads:[~2012-02-24  0:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-24  0:05 [ 00/10] 3.2.8-stable review Greg KH
2012-02-24  0:02 ` [ 01/10] i387: math_state_restore() isnt called from asm Greg KH
2012-02-24  0:02 ` [ 02/10] i387: make irq_fpu_usable() tests more robust Greg KH
2012-02-24  0:02 ` Greg KH [this message]
2012-02-24  0:02 ` [ 04/10] i387: fix x86-64 preemption-unsafe user stack save/restore Greg KH
2012-02-24  0:02 ` [ 05/10] i387: move TS_USEDFPU clearing out of __save_init_fpu and into callers Greg KH
2012-02-24  0:02 ` [ 06/10] i387: dont ever touch TS_USEDFPU directly, use helper functions Greg KH
2012-02-24  0:02 ` [ 07/10] i387: do not preload FPU state at task switch time Greg KH
2012-02-24  0:02 ` [ 08/10] i387: move AMD K7/K8 fpu fxsave/fxrstor workaround from save to restore Greg KH
2012-02-24  0:02 ` [ 09/10] i387: move TS_USEDFPU flag from thread_info to task_struct Greg KH
2012-02-24  0:02 ` [ 10/10] i387: re-introduce FPU state preloading at context switch time Greg KH

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