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, Heiko Carstens , Martin Schwidefsky Subject: [ 28/48] s390/mm: fix flush_tlb_kernel_range() Date: Mon, 18 Mar 2013 14:08:36 -0700 Message-Id: <20130318210812.247446196@linuxfoundation.org> In-Reply-To: <20130318210810.247845918@linuxfoundation.org> References: <20130318210810.247845918@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens commit f6a70a07079518280022286a1dceb797d12e1edf upstream. Our flush_tlb_kernel_range() implementation calls __tlb_flush_mm() with &init_mm as argument. __tlb_flush_mm() however will only flush tlbs for the passed in mm if its mm_cpumask is not empty. For the init_mm however its mm_cpumask has never any bits set. Which in turn means that our flush_tlb_kernel_range() implementation doesn't work at all. This can be easily verified with a vmalloc/vfree loop which allocates a page, writes to it and then frees the page again. A crash will follow almost instantly. To fix this remove the cpumask_empty() check in __tlb_flush_mm() since there shouldn't be too many mms with a zero mm_cpumask, besides the init_mm of course. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/include/asm/tlbflush.h | 2 -- 1 file changed, 2 deletions(-) --- a/arch/s390/include/asm/tlbflush.h +++ b/arch/s390/include/asm/tlbflush.h @@ -74,8 +74,6 @@ static inline void __tlb_flush_idte(unsi static inline void __tlb_flush_mm(struct mm_struct * mm) { - if (unlikely(cpumask_empty(mm_cpumask(mm)))) - return; /* * If the machine has IDTE we prefer to do a per mm flush * on all cpus instead of doing a local flush if the mm