| From f6a70a07079518280022286a1dceb797d12e1edf Mon Sep 17 00:00:00 2001 |
| From: Heiko Carstens <heiko.carstens@de.ibm.com> |
| Date: Mon, 4 Mar 2013 14:14:11 +0100 |
| Subject: s390/mm: fix flush_tlb_kernel_range() |
| |
| From: Heiko Carstens <heiko.carstens@de.ibm.com> |
| |
| 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 <heiko.carstens@de.ibm.com> |
| Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| 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 |
