From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mel Gorman , "Paul E. McKenney" , Rik van Riel , Andrew Morton , Linus Torvalds Subject: [PATCH 3.10 074/129] mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates Date: Mon, 6 Jan 2014 14:38:23 -0800 Message-Id: <20140106223901.729801564@linuxfoundation.org> In-Reply-To: <20140106223859.589799655@linuxfoundation.org> References: <20140106223859.589799655@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mel Gorman commit af2c1401e6f9177483be4fad876d0073669df9df upstream. According to documentation on barriers, stores issued before a LOCK can complete after the lock implying that it's possible tlb_flush_pending can be visible after a page table update. As per revised documentation, this patch adds a smp_mb__before_spinlock to guarantee the correct ordering. Signed-off-by: Mel Gorman Acked-by: Paul E. McKenney Reviewed-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/mm_types.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -480,7 +480,12 @@ static inline bool mm_tlb_flush_pending( static inline void set_tlb_flush_pending(struct mm_struct *mm) { mm->tlb_flush_pending = true; - barrier(); + + /* + * Guarantee that the tlb_flush_pending store does not leak into the + * critical section updating the page tables + */ + smp_mb__before_spinlock(); } /* Clearing is done after a TLB flush, which also provides a barrier. */ static inline void clear_tlb_flush_pending(struct mm_struct *mm)