| Date | Mon, 25 Mar 2013 01:05:44 +0000 | From | Ben Hutchings <> | Subject | [ 020/104] s390/mm: fix flush_tlb_kernel_range() |
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3.2-stable review patch. If anyone has any objections, please let me know.
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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: Ben Hutchings <ben@decadent.org.uk> --- 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
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