4.18-stable review patch. If anyone has any objections, please let me know.
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From: Vasily Gorbik gor@linux.ibm.com
[ Upstream commit 5bedf8aa03c28cb8dc98bdd32a41b66d8f7d3eaa ]
Since proc_dointvec does not perform value range control, proc_dointvec_minmax should be used to limit value range, which is clearly intended here, as the internal representation of the value:
unsigned int alloc_pgste:1;
In fact it currently works, since we have
mm->context.alloc_pgste = page_table_allocate_pgste || ...
... since commit 23fefe119ceb5 ("s390/kvm: avoid global config of vm.alloc_pgste=1")
Before that it was
mm->context.alloc_pgste = page_table_allocate_pgste;
which was broken. That was introduced with commit 0b46e0a3ec0d7 ("s390/kvm: remove delayed reallocation of page tables for KVM").
Fixes: 0b46e0a3ec0d7 ("s390/kvm: remove delayed reallocation of page tables for KVM") Acked-by: Christian Borntraeger borntraeger@de.ibm.com Reviewed-by: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/mm/pgalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -28,7 +28,7 @@ static struct ctl_table page_table_sysct .data = &page_table_allocate_pgste, .maxlen = sizeof(int), .mode = S_IRUGO | S_IWUSR, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, .extra1 = &page_table_allocate_pgste_min, .extra2 = &page_table_allocate_pgste_max, },