4.14-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 8d306f53b63099fec2d56300149e400d181ba4f5 upstream.
Martin Cermak reported that setting a uprobe doesn't work. Reason for this is that the common uprobes code tries to get an unmapped area at the last possible page within an address space.
This broke with commit 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") which introduced an off-by-one bug which prevents to map anything at the last possible page within an address space.
The check with the off-by-one bug however can be removed since with commit 8ab867cb0806 ("s390/mm: fix BUG_ON in crst_table_upgrade") the necessary check is done at both call sites.
Reported-by: Martin Cermak mcermak@redhat.com Bisected-by: Thomas Richter tmricht@linux.vnet.ibm.com Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") Reviewed-by: Hendrik Brueckner brueckner@linux.vnet.ibm.com 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/mm/pgalloc.c | 2 -- 1 file changed, 2 deletions(-)
--- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -85,8 +85,6 @@ int crst_table_upgrade(struct mm_struct
/* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE); - if (end >= TASK_SIZE_MAX) - return -ENOMEM; rc = 0; notify = 0; while (mm->context.asce_limit < end) {