linux-kernel - [PATCH 4.9 008/105] parisc: Extend disabled preemption in copy_user

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Date:   Fri,  4 Aug 2017 16:14:36 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, John David Anglin <dave.anglin@...l.net>,
        Helge Deller <deller@....de>
Subject: [PATCH 4.9 008/105] parisc: Extend disabled preemption in copy_user_page

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

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

From: John David Anglin <dave.anglin@...l.net>

commit 56008c04ebc099940021b714da2d7779117cf6a7 upstream.

It's always bothered me that we only disable preemption in
copy_user_page around the call to flush_dcache_page_asm.
This patch extends this to after the copy.

Signed-off-by: John David Anglin <dave.anglin@...l.net>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/parisc/kernel/cache.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -452,8 +452,8 @@ void copy_user_page(void *vto, void *vfr
 	  before it can be accessed through the kernel mapping. */
 	preempt_disable();
 	flush_dcache_page_asm(__pa(vfrom), vaddr);
-	preempt_enable();
 	copy_page_asm(vto, vfrom);
+	preempt_enable();
 }
 EXPORT_SYMBOL(copy_user_page);